NEWS
author haftmann
Wed Mar 12 08:47:35 2008 +0100 (2008-03-12)
changeset 26259 d30f4a509361
parent 26231 cd9d7f449369
child 26315 cb3badaa192e
permissions -rw-r--r--
better improvement in instantiation target
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Syntax: symbol \<chi> is now considered a letter.  Potential
    10 INCOMPATIBILITY in identifier syntax etc.
    11 
    12 * Outer syntax: string tokens may contain arbitrary character codes
    13 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
    14 "foo_bar".
    15 
    16 * Outer syntax: string tokens no longer admit escaped white space,
    17 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
    18 white space directly.
    19 
    20 * Theory loader: use_thy (and similar operations) no longer set the
    21 implicit ML context, which was occasionally hard to predict and in
    22 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
    23 provides a proper context already.
    24 
    25 
    26 *** Pure ***
    27 
    28 * Instantiation target allows for simultaneous specification of class
    29 instance operations together with an instantiation proof.
    30 Type-checking phase allows to refer to class operations uniformly.
    31 See HOL/Complex/Complex.thy for an Isar example and
    32 HOL/Library/Eval.thy for an ML example.
    33 
    34 * Indexing of literal facts: be more serious about including only
    35 facts from the visible specification/proof context, but not the
    36 background context (locale etc.).  Affects `prop` notation and method
    37 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    38 situations.
    39 
    40 
    41 *** HOL ***
    42 
    43 * Library/Option_ord.thy: Canonical order on option type.
    44 
    45 * Library/RBT.thy: New theory of red-black trees, an efficient
    46 implementation of finite maps.
    47 
    48 * Library/Countable.thy: Type class for countable types.
    49 
    50 * Theory Int: The representation of numerals has changed.  The infix
    51 operator BIT and the bit datatype with constructors B0 and B1 have
    52 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    53 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    54 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    55 accordingly.
    56 
    57 * Theory Nat: definition of <= and < on natural numbers no longer
    58 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    59 le_def and less_def have disappeared.  Consider lemmas not_less
    60 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    61 
    62 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    63 (whose purpose mainly is for various fold_set functionals) have been
    64 abandoned in favour of the existing algebraic classes
    65 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
    66 lower_semilattice (resp. upper_semilattice) and linorder.
    67 INCOMPATIBILITY.
    68 
    69 * Theory Transitive_Closure: induct and cases rules now declare proper
    70 case_names ("base" and "step").  INCOMPATIBILITY.
    71 
    72 * Theorem Inductive.lfp_ordinal_induct generalized to complete
    73 lattices.  The form set-specific version is available as
    74 Inductive.lfp_ordinal_induct_set.
    75 
    76 * Theorems "power.simps" renamed to "power_int.simps".
    77 
    78 * Class semiring_div provides basic abstract properties of semirings
    79 with division and modulo operations.  Subsumes former class dvd_mod.
    80 
    81 * Merged theories IntDef, Numeral and IntArith into unified theory
    82 Int.  INCOMPATIBILITY.
    83 
    84 * Theory Library/Code_Index: type "index" now represents natural
    85 numbers rather than integers.  INCOMPATIBILITY.
    86 
    87 * New class "uminus" with operation "uminus" (split of from class
    88 "minus" which now only has operation "minus", binary).
    89 INCOMPATIBILITY.
    90 
    91 * New primrec package.  Specification syntax conforms in style to
    92 definition/function/....  No separate induction rule is provided.  The
    93 "primrec" command distinguishes old-style and new-style specifications
    94 by syntax.  The former primrec package is now named OldPrimrecPackage.
    95 When adjusting theories, beware: constants stemming for new-style
    96 primrec specifications have authentic syntax.
    97 
    98 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
    99 
   100 * Library/ListVector: new theory of arithmetic vector operations.
   101 
   102 * Constants "card", "internal_split", "option_map" now with authentic
   103 syntax.  INCOMPATIBILITY.
   104 
   105 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   106 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   107 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   108 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   109 Sup_set_def, le_def, less_def, option_map_def now with object
   110 equality.  INCOMPATIBILITY.
   111 
   112 * Method "induction_scheme" derives user-specified induction rules
   113 from wellfounded induction and completeness of patterns. This factors
   114 out some operations that are done internally by the function package
   115 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   116 for examples,
   117 
   118 * Records. Removed K_record, and replaced it by pure lambda term
   119 %x. c. The simplifier setup is now more robust against eta expansion.
   120 INCOMPATIBILITY: in cases explicitly referring to K_record.
   121 
   122 * Metis prover is now an order of magnitude faster, and also works
   123 with multithreading.
   124 
   125 
   126 *** ZF ***
   127 
   128 * Renamed theories:
   129 
   130   Datatype.thy  -> Datatype_ZF.thy
   131   Inductive.thy -> Inductive_ZF.thy
   132   Int.thy       -> Int_ZF.thy
   133   IntDiv.thy    -> IntDiv_ZF.thy
   134   Nat.thy       -> Nat_ZF.thy
   135   List.thy      -> List_ZF.thy
   136   Main.thy      -> Main_ZF.thy
   137 
   138  This is to allow to load both ZF and HOL in the same session.
   139 
   140  INCOMPATIBILITY: ZF theories that import individual theories below
   141  Main might need to be adapted. For compatibility, a new 
   142  "theory Main imports Main_ZF begin end" is provided, so if you just
   143  imported "Main", no changes are needed.
   144 
   145 
   146 *** ML ***
   147 
   148 * ML within Isar: antiquotation @{const name} or @{const
   149 name(typargs)} produces statically-checked Const term.
   150 
   151 * The ``print mode'' is now a thread-local value derived from a global
   152 template (the former print_mode reference), thus access becomes
   153 non-critical.  The global print_mode reference is for session
   154 management only; user-code should use print_mode_value,
   155 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   156 
   157 * system/system_out provides a robust way to invoke external shell
   158 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   159 use OS.Process.system etc. directly.
   160 
   161 
   162 *** System ***
   163 
   164 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   165 documented way of changing the user's settings is via
   166 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   167 script.
   168 
   169 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   170 in accordance with Proof General 3.7, which prefers GNU emacs.
   171 
   172 * Multithreading.max_threads := 0 refers to the number of actual CPU
   173 cores of the underlying machine, which is a good starting point for
   174 optimal performance tuning.  The corresponding usedir option -M allows
   175 "max" as an alias for "0".  WARNING: does not work on certain versions
   176 of Mac OS (with Poly/ML 5.1).
   177 
   178 * isatool tty runs Isabelle process with plain tty interaction;
   179 optional line editor may be specified via ISABELLE_LINE_EDITOR
   180 setting, the default settings attempt to locate "ledit" and "rlwrap".
   181 
   182 * isatool browser now works with Cygwin as well, using general
   183 "javapath" function defined in Isabelle process environment.
   184 
   185 * isabelle-process: non-ML sessions are run with "nice", to prevent
   186 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   187 XEmacs).
   188 
   189 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   190 provides general wrapper for managing an Isabelle process in a robust
   191 fashion, with ``cooked'' output from stdin/stderr.
   192 
   193 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   194 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   195 
   196 
   197 
   198 New in Isabelle2007 (November 2007)
   199 -----------------------------------
   200 
   201 *** General ***
   202 
   203 * More uniform information about legacy features, notably a
   204 warning/error of "Legacy feature: ...", depending on the state of the
   205 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   206 legacy features will disappear eventually.
   207 
   208 * Theory syntax: the header format ``theory A = B + C:'' has been
   209 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   210 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   211 
   212 * Theory syntax: the old non-Isar theory file format has been
   213 discontinued altogether.  Note that ML proof scripts may still be used
   214 with Isar theories; migration is usually quite simple with the ML
   215 function use_legacy_bindings.  INCOMPATIBILITY.
   216 
   217 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   218 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   219 quotes.
   220 
   221 * Theory loader: be more serious about observing the static theory
   222 header specifications (including optional directories), but not the
   223 accidental file locations of previously successful loads.  The strict
   224 update policy of former update_thy is now already performed by
   225 use_thy, so the former has been removed; use_thys updates several
   226 theories simultaneously, just as 'imports' within a theory header
   227 specification, but without merging the results.  Potential
   228 INCOMPATIBILITY: may need to refine theory headers and commands
   229 ROOT.ML which depend on load order.
   230 
   231 * Theory loader: optional support for content-based file
   232 identification, instead of the traditional scheme of full physical
   233 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   234 (cf. the system manual).  The new scheme allows to work with
   235 non-finished theories in persistent session images, such that source
   236 files may be moved later on without requiring reloads.
   237 
   238 * Theory loader: old-style ML proof scripts being *attached* to a thy
   239 file (with the same base name as the theory) are considered a legacy
   240 feature, which will disappear eventually. Even now, the theory loader
   241 no longer maintains dependencies on such files.
   242 
   243 * Syntax: the scope for resolving ambiguities via type-inference is
   244 now limited to individual terms, instead of whole simultaneous
   245 specifications as before. This greatly reduces the complexity of the
   246 syntax module and improves flexibility by separating parsing and
   247 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   248 'fixes' etc.) are required in rare situations.
   249 
   250 * Syntax: constants introduced by new-style packages ('definition',
   251 'abbreviation' etc.) are passed through the syntax module in
   252 ``authentic mode''. This means that associated mixfix annotations
   253 really stick to such constants, independently of potential name space
   254 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   255 trees are represented slightly differently, may need to adapt syntax
   256 translations accordingly. Use CONST marker in 'translations' and
   257 @{const_syntax} antiquotation in 'parse_translation' etc.
   258 
   259 * Legacy goal package: reduced interface to the bare minimum required
   260 to keep existing proof scripts running.  Most other user-level
   261 functions are now part of the OldGoals structure, which is *not* open
   262 by default (consider isatool expandshort before open OldGoals).
   263 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   264 these tend to cause confusion about the actual goal (!) context being
   265 used here, which is not necessarily the same as the_context().
   266 
   267 * Command 'find_theorems': supports "*" wild-card in "name:"
   268 criterion; "with_dups" option.  Certain ProofGeneral versions might
   269 support a specific search form (see ProofGeneral/CHANGES).
   270 
   271 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   272 by default, which means that "prems" (and also "fixed variables") are
   273 suppressed from proof state output.  Note that the ProofGeneral
   274 settings mechanism allows to change and save options persistently, but
   275 older versions of Isabelle will fail to start up if a negative prems
   276 limit is imposed.
   277 
   278 * Local theory targets may be specified by non-nested blocks of
   279 ``context/locale/class ... begin'' followed by ``end''.  The body may
   280 contain definitions, theorems etc., including any derived mechanism
   281 that has been implemented on top of these primitives.  This concept
   282 generalizes the existing ``theorem (in ...)'' towards more versatility
   283 and scalability.
   284 
   285 * Proof General interface: proper undo of final 'end' command;
   286 discontinued Isabelle/classic mode (ML proof scripts).
   287 
   288 
   289 *** Document preparation ***
   290 
   291 * Added antiquotation @{theory name} which prints the given name,
   292 after checking that it refers to a valid ancestor theory in the
   293 current context.
   294 
   295 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   296 check the given source text as ML type/structure, printing verbatim.
   297 
   298 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   299 "c args == rhs" given in the current context.  (Any number of
   300 arguments may be given on the LHS.)
   301 
   302 
   303 *** Pure ***
   304 
   305 * The 'class' package offers a combination of axclass and locale to
   306 achieve Haskell-like type classes in Isabelle.  Definitions and
   307 theorems within a class context produce both relative results (with
   308 implicit parameters according to the locale context), and polymorphic
   309 constants with qualified polymorphism (according to the class
   310 context).  Within the body context of a 'class' target, a separate
   311 syntax layer ("user space type system") takes care of converting
   312 between global polymorphic consts and internal locale representation.
   313 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   314 "isatool doc classes" provides a tutorial.
   315 
   316 * Generic code generator framework allows to generate executable
   317 code for ML and Haskell (including Isabelle classes).  A short usage
   318 sketch:
   319 
   320     internal compilation:
   321         export_code <list of constants (term syntax)> in SML
   322     writing SML code to a file:
   323         export_code <list of constants (term syntax)> in SML <filename>
   324     writing OCaml code to a file:
   325         export_code <list of constants (term syntax)> in OCaml <filename>
   326     writing Haskell code to a bunch of files:
   327         export_code <list of constants (term syntax)> in Haskell <filename>
   328 
   329     evaluating closed propositions to True/False using code generation:
   330         method ``eval''
   331 
   332 Reasonable default setup of framework in HOL.
   333 
   334 Theorem attributs for selecting and transforming function equations theorems:
   335 
   336     [code fun]:        select a theorem as function equation for a specific constant
   337     [code fun del]:    deselect a theorem as function equation for a specific constant
   338     [code inline]:     select an equation theorem for unfolding (inlining) in place
   339     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   340 
   341 User-defined serializations (target in {SML, OCaml, Haskell}):
   342 
   343     code_const <and-list of constants (term syntax)>
   344       {(target) <and-list of const target syntax>}+
   345 
   346     code_type <and-list of type constructors>
   347       {(target) <and-list of type target syntax>}+
   348 
   349     code_instance <and-list of instances>
   350       {(target)}+
   351         where instance ::= <type constructor> :: <class>
   352 
   353     code_class <and_list of classes>
   354       {(target) <and-list of class target syntax>}+
   355         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   356 
   357 code_instance and code_class only are effective to target Haskell.
   358 
   359 For example usage see src/HOL/ex/Codegenerator.thy and
   360 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   361 generation from Isabelle/HOL theories is available via "isatool doc
   362 codegen".
   363 
   364 * Code generator: consts in 'consts_code' Isar commands are now
   365 referred to by usual term syntax (including optional type
   366 annotations).
   367 
   368 * Command 'no_translations' removes translation rules from theory
   369 syntax.
   370 
   371 * Overloaded definitions are now actually checked for acyclic
   372 dependencies.  The overloading scheme is slightly more general than
   373 that of Haskell98, although Isabelle does not demand an exact
   374 correspondence to type class and instance declarations.
   375 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   376 exotic versions of overloading -- at the discretion of the user!
   377 
   378 Polymorphic constants are represented via type arguments, i.e. the
   379 instantiation that matches an instance against the most general
   380 declaration given in the signature.  For example, with the declaration
   381 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   382 as c(nat).  Overloading is essentially simultaneous structural
   383 recursion over such type arguments.  Incomplete specification patterns
   384 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   385 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   386 Command 'print_theory' outputs the normalized system of recursive
   387 equations, see section "definitions".
   388 
   389 * Configuration options are maintained within the theory or proof
   390 context (with name and type bool/int/string), providing a very simple
   391 interface to a poor-man's version of general context data.  Tools may
   392 declare options in ML (e.g. using Attrib.config_int) and then refer to
   393 these values using Config.get etc.  Users may change options via an
   394 associated attribute of the same name.  This form of context
   395 declaration works particularly well with commands 'declare' or
   396 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   397 very easy to avoid global references, which would not observe Isar
   398 toplevel undo/redo and fail to work with multithreading.
   399 
   400 Various global ML references of Pure and HOL have been turned into
   401 configuration options:
   402 
   403   Unify.search_bound		unify_search_bound
   404   Unify.trace_bound		unify_trace_bound
   405   Unify.trace_simp		unify_trace_simp
   406   Unify.trace_types		unify_trace_types
   407   Simplifier.simp_depth_limit	simp_depth_limit
   408   Blast.depth_limit		blast_depth_limit
   409   DatatypeProp.dtK		datatype_distinctness_limit
   410   fast_arith_neq_limit  	fast_arith_neq_limit
   411   fast_arith_split_limit	fast_arith_split_limit
   412 
   413 * Named collections of theorems may be easily installed as context
   414 data using the functor NamedThmsFun (see also
   415 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   416 attributes; there is also a toplevel print command.  This facility is
   417 just a common case of general context data, which is the preferred way
   418 for anything more complex than just a list of facts in canonical
   419 order.
   420 
   421 * Isar: command 'declaration' augments a local theory by generic
   422 declaration functions written in ML.  This enables arbitrary content
   423 being added to the context, depending on a morphism that tells the
   424 difference of the original declaration context wrt. the application
   425 context encountered later on.
   426 
   427 * Isar: proper interfaces for simplification procedures.  Command
   428 'simproc_setup' declares named simprocs (with match patterns, and body
   429 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   430 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   431 
   432 * Isar: an extra pair of brackets around attribute declarations
   433 abbreviates a theorem reference involving an internal dummy fact,
   434 which will be ignored later --- only the effect of the attribute on
   435 the background context will persist.  This form of in-place
   436 declarations is particularly useful with commands like 'declare' and
   437 'using', for example ``have A using [[simproc a]] by simp''.
   438 
   439 * Isar: method "assumption" (and implicit closing of subproofs) now
   440 takes simple non-atomic goal assumptions into account: after applying
   441 an assumption as a rule the resulting subgoals are solved by atomic
   442 assumption steps.  This is particularly useful to finish 'obtain'
   443 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   444 without referring to the original premise "!!x. P x ==> thesis" in the
   445 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   446 more permissive.
   447 
   448 * Isar: implicit use of prems from the Isar proof context is
   449 considered a legacy feature.  Common applications like ``have A .''
   450 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   451 referencing facts explicitly here improves readability and
   452 maintainability of proof texts.
   453 
   454 * Isar: improper proof element 'guess' is like 'obtain', but derives
   455 the obtained context from the course of reasoning!  For example:
   456 
   457   assume "EX x y. A x & B y"   -- "any previous fact"
   458   then guess x and y by clarify
   459 
   460 This technique is potentially adventurous, depending on the facts and
   461 proof tools being involved here.
   462 
   463 * Isar: known facts from the proof context may be specified as literal
   464 propositions, using ASCII back-quote syntax.  This works wherever
   465 named facts used to be allowed so far, in proof commands, proof
   466 methods, attributes etc.  Literal facts are retrieved from the context
   467 according to unification of type and term parameters.  For example,
   468 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   469 theorems in the current context, then these are valid literal facts:
   470 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   471 
   472 There is also a proof method "fact" which does the same composition
   473 for explicit goal states, e.g. the following proof texts coincide with
   474 certain special cases of literal facts:
   475 
   476   have "A" by fact                 ==  note `A`
   477   have "A ==> B" by fact           ==  note `A ==> B`
   478   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   479   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   480 
   481 * Isar: ":" (colon) is no longer a symbolic identifier character in
   482 outer syntax.  Thus symbolic identifiers may be used without
   483 additional white space in declarations like this: ``assume *: A''.
   484 
   485 * Isar: 'print_facts' prints all local facts of the current context,
   486 both named and unnamed ones.
   487 
   488 * Isar: 'def' now admits simultaneous definitions, e.g.:
   489 
   490   def x == "t" and y == "u"
   491 
   492 * Isar: added command 'unfolding', which is structurally similar to
   493 'using', but affects both the goal state and facts by unfolding given
   494 rewrite rules.  Thus many occurrences of the 'unfold' method or
   495 'unfolded' attribute may be replaced by first-class proof text.
   496 
   497 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   498 and command 'unfolding' now all support object-level equalities
   499 (potentially conditional).  The underlying notion of rewrite rule is
   500 analogous to the 'rule_format' attribute, but *not* that of the
   501 Simplifier (which is usually more generous).
   502 
   503 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   504 premises of a theorem by n. Useful in conjunction with drule.
   505 
   506 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   507 method expression within a sandbox consisting of the first N
   508 sub-goals, which need to exist.  For example, ``simp_all [3]''
   509 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   510 simplifies all new goals that emerge from applying rule foo to the
   511 originally first one.
   512 
   513 * Isar: schematic goals are no longer restricted to higher-order
   514 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   515 expected.
   516 
   517 * Isar: the conclusion of a long theorem statement is now either
   518 'shows' (a simultaneous conjunction, as before), or 'obtains'
   519 (essentially a disjunction of cases with local parameters and
   520 assumptions).  The latter allows to express general elimination rules
   521 adequately; in this notation common elimination rules look like this:
   522 
   523   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   524     assumes "EX x. P x"
   525     obtains x where "P x"
   526 
   527   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   528     assumes "A & B"
   529     obtains A and B
   530 
   531   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   532     assumes "A | B"
   533     obtains
   534       A
   535     | B
   536 
   537 The subsequent classical rules even refer to the formal "thesis"
   538 explicitly:
   539 
   540   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   541     obtains "~ thesis"
   542 
   543   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   544     obtains "thesis ==> something"
   545 
   546 The actual proof of an 'obtains' statement is analogous to that of the
   547 Isar proof element 'obtain', only that there may be several cases.
   548 Optional case names may be specified in parentheses; these will be
   549 available both in the present proof and as annotations in the
   550 resulting rule, for later use with the 'cases' method (cf. attribute
   551 case_names).
   552 
   553 * Isar: the assumptions of a long theorem statement are available as
   554 "assms" fact in the proof context.  This is more appropriate than the
   555 (historical) "prems", which refers to all assumptions of the current
   556 context, including those from the target locale, proof body etc.
   557 
   558 * Isar: 'print_statement' prints theorems from the current theory or
   559 proof context in long statement form, according to the syntax of a
   560 top-level lemma.
   561 
   562 * Isar: 'obtain' takes an optional case name for the local context
   563 introduction rule (default "that").
   564 
   565 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   566 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   567 to occur.
   568 
   569 * Pure: syntax "CONST name" produces a fully internalized constant
   570 according to the current context.  This is particularly useful for
   571 syntax translations that should refer to internal constant
   572 representations independently of name spaces.
   573 
   574 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   575 instead of "FOO ". This allows multiple binder declarations to coexist
   576 in the same context.  INCOMPATIBILITY.
   577 
   578 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   579 primitive that also works in a locale context (both for constants and
   580 fixed variables). Type declaration and internal syntactic representation
   581 of given constants retrieved from the context. Likewise, the
   582 'no_notation' command allows to remove given syntax annotations from the
   583 current context.
   584 
   585 * Isar/locales: new derived specification elements 'axiomatization',
   586 'definition', 'abbreviation', which support type-inference, admit
   587 object-level specifications (equality, equivalence).  See also the
   588 isar-ref manual.  Examples:
   589 
   590   axiomatization
   591     eq  (infix "===" 50) where
   592     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   593 
   594   definition "f x y = x + y + 1"
   595   definition g where "g x = f x x"
   596 
   597   abbreviation
   598     neq  (infix "=!=" 50) where
   599     "x =!= y == ~ (x === y)"
   600 
   601 These specifications may be also used in a locale context.  Then the
   602 constants being introduced depend on certain fixed parameters, and the
   603 constant name is qualified by the locale base name.  An internal
   604 abbreviation takes care for convenient input and output, making the
   605 parameters implicit and using the original short name.  See also
   606 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   607 entities from a monomorphic theory.
   608 
   609 Presently, abbreviations are only available 'in' a target locale, but
   610 not inherited by general import expressions.  Also note that
   611 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   612 'translations' in common applications.  The "no_abbrevs" print mode
   613 prevents folding of abbreviations in term output.
   614 
   615 Concrete syntax is attached to specified constants in internal form,
   616 independently of name spaces.  The parse tree representation is
   617 slightly different -- use 'notation' instead of raw 'syntax', and
   618 'translations' with explicit "CONST" markup to accommodate this.
   619 
   620 * Pure/Isar: unified syntax for new-style specification mechanisms
   621 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   622 full type inference and dummy patterns ("_").  For example:
   623 
   624   definition "K x _ = x"
   625 
   626   inductive conj for A B
   627   where "A ==> B ==> conj A B"
   628 
   629 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   630 the current context.  Print mode "no_abbrevs" prevents inversion of
   631 abbreviations on output.
   632 
   633 * Isar/locales: improved parameter handling: use of locales "var" and
   634 "struct" no longer necessary; - parameter renamings are no longer
   635 required to be injective.  For example, this allows to define
   636 endomorphisms as locale endom = homom mult mult h.
   637 
   638 * Isar/locales: changed the way locales with predicates are defined.
   639 Instead of accumulating the specification, the imported expression is
   640 now an interpretation.  INCOMPATIBILITY: different normal form of
   641 locale expressions.  In particular, in interpretations of locales with
   642 predicates, goals repesenting already interpreted fragments are not
   643 removed automatically.  Use methods `intro_locales' and
   644 `unfold_locales'; see below.
   645 
   646 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   647 provide backward reasoning on locales predicates.  The methods are
   648 aware of interpretations and discharge corresponding goals.
   649 `intro_locales' is less aggressive then `unfold_locales' and does not
   650 unfold predicates to assumptions.
   651 
   652 * Isar/locales: the order in which locale fragments are accumulated
   653 has changed.  This enables to override declarations from fragments due
   654 to interpretations -- for example, unwanted simp rules.
   655 
   656 * Isar/locales: interpretation in theories and proof contexts has been
   657 extended.  One may now specify (and prove) equations, which are
   658 unfolded in interpreted theorems.  This is useful for replacing
   659 defined concepts (constants depending on locale parameters) by
   660 concepts already existing in the target context.  Example:
   661 
   662   interpretation partial_order ["op <= :: [int, int] => bool"]
   663     where "partial_order.less (op <=) (x::int) y = (x < y)"
   664 
   665 Typically, the constant `partial_order.less' is created by a
   666 definition specification element in the context of locale
   667 partial_order.
   668 
   669 * Method "induct": improved internal context management to support
   670 local fixes and defines on-the-fly. Thus explicit meta-level
   671 connectives !!  and ==> are rarely required anymore in inductive goals
   672 (using object-logic connectives for this purpose has been long
   673 obsolete anyway). Common proof patterns are explained in
   674 src/HOL/Induct/Common_Patterns.thy, see also
   675 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   676 examples.
   677 
   678 * Method "induct": improved handling of simultaneous goals. Instead of
   679 introducing object-level conjunction, the statement is now split into
   680 several conclusions, while the corresponding symbolic cases are nested
   681 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   682 see src/HOL/Induct/Common_Patterns.thy, for example.
   683 
   684 * Method "induct": mutual induction rules are now specified as a list
   685 of rule sharing the same induction cases. HOL packages usually provide
   686 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   687 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   688 mutual induction rules differently, i.e. like this:
   689 
   690   (induct rule: foo_bar.inducts)
   691   (induct set: foo bar)
   692   (induct pred: foo bar)
   693   (induct type: foo bar)
   694 
   695 The ML function ProjectRule.projections turns old-style rules into the
   696 new format.
   697 
   698 * Method "coinduct": dual of induction, see
   699 src/HOL/Library/Coinductive_List.thy for various examples.
   700 
   701 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   702 considered a legacy feature.
   703 
   704 * Attribute "symmetric" produces result with standardized schematic
   705 variables (index 0).  Potential INCOMPATIBILITY.
   706 
   707 * Simplifier: by default the simplifier trace only shows top level
   708 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   709 default. Thus there is less danger of being flooded by the trace. The
   710 trace indicates where parts have been suppressed.
   711   
   712 * Provers/classical: removed obsolete classical version of elim_format
   713 attribute; classical elim/dest rules are now treated uniformly when
   714 manipulating the claset.
   715 
   716 * Provers/classical: stricter checks to ensure that supplied intro,
   717 dest and elim rules are well-formed; dest and elim rules must have at
   718 least one premise.
   719 
   720 * Provers/classical: attributes dest/elim/intro take an optional
   721 weight argument for the rule (just as the Pure versions).  Weights are
   722 ignored by automated tools, but determine the search order of single
   723 rule steps.
   724 
   725 * Syntax: input syntax now supports dummy variable binding "%_. b",
   726 where the body does not mention the bound variable.  Note that dummy
   727 patterns implicitly depend on their context of bounds, which makes
   728 "{_. _}" match any set comprehension as expected.  Potential
   729 INCOMPATIBILITY -- parse translations need to cope with syntactic
   730 constant "_idtdummy" in the binding position.
   731 
   732 * Syntax: removed obsolete syntactic constant "_K" and its associated
   733 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   734 for example "A -> B" => "Pi A (%_. B)".
   735 
   736 * Pure: 'class_deps' command visualizes the subclass relation, using
   737 the graph browser tool.
   738 
   739 * Pure: 'print_theory' now suppresses certain internal declarations by
   740 default; use '!' option for full details.
   741 
   742 
   743 *** HOL ***
   744 
   745 * Method "metis" proves goals by applying the Metis general-purpose
   746 resolution prover (see also http://gilith.com/software/metis/).
   747 Examples are in the directory MetisExamples.  WARNING: the
   748 Isabelle/HOL-Metis integration does not yet work properly with
   749 multi-threading.
   750   
   751 * Command 'sledgehammer' invokes external automatic theorem provers as
   752 background processes.  It generates calls to the "metis" method if
   753 successful. These can be pasted into the proof.  Users do not have to
   754 wait for the automatic provers to return.  WARNING: does not really
   755 work with multi-threading.
   756 
   757 * New "auto_quickcheck" feature tests outermost goal statements for
   758 potential counter-examples.  Controlled by ML references
   759 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   760 5000 milliseconds).  Fails silently if statements is outside of
   761 executable fragment, or any other codgenerator problem occurs.
   762 
   763 * New constant "undefined" with axiom "undefined x = undefined".
   764 
   765 * Added class "HOL.eq", allowing for code generation with polymorphic
   766 equality.
   767 
   768 * Some renaming of class constants due to canonical name prefixing in
   769 the new 'class' package:
   770 
   771     HOL.abs ~> HOL.abs_class.abs
   772     HOL.divide ~> HOL.divide_class.divide
   773     0 ~> HOL.zero_class.zero
   774     1 ~> HOL.one_class.one
   775     op + ~> HOL.plus_class.plus
   776     op - ~> HOL.minus_class.minus
   777     uminus ~> HOL.minus_class.uminus
   778     op * ~> HOL.times_class.times
   779     op < ~> HOL.ord_class.less
   780     op <= > HOL.ord_class.less_eq
   781     Nat.power ~> Power.power_class.power
   782     Nat.size ~> Nat.size_class.size
   783     Numeral.number_of ~> Numeral.number_class.number_of
   784     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   785     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   786     Orderings.min ~> Orderings.ord_class.min
   787     Orderings.max ~> Orderings.ord_class.max
   788     Divides.op div ~> Divides.div_class.div
   789     Divides.op mod ~> Divides.div_class.mod
   790     Divides.op dvd ~> Divides.div_class.dvd
   791 
   792 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   793 
   794 a) User-defined constants using any of the names "plus", "minus",
   795 "times", "less" or "less_eq". The standard syntax translations for
   796 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   797 names.
   798 
   799 b) Variables named "plus", "minus", "times", "less", "less_eq"
   800 INCOMPATIBILITY: use more specific names.
   801 
   802 c) Permutative equations (e.g. "a + b = b + a")
   803 Since the change of names also changes the order of terms, permutative
   804 rewrite rules may get applied in a different order. Experience shows
   805 that this is rarely the case (only two adaptions in the whole Isabelle
   806 distribution).  INCOMPATIBILITY: rewrite proofs
   807 
   808 d) ML code directly refering to constant names
   809 This in general only affects hand-written proof tactics, simprocs and
   810 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   811 Consider using @{const_name} antiquotation.
   812 
   813 * New class "default" with associated constant "default".
   814 
   815 * Function "sgn" is now overloaded and available on int, real, complex
   816 (and other numeric types), using class "sgn".  Two possible defs of
   817 sgn are given as equational assumptions in the classes sgn_if and
   818 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   819 INCOMPATIBILITY.
   820 
   821 * Locale "partial_order" now unified with class "order" (cf. theory
   822 Orderings), added parameter "less".  INCOMPATIBILITY.
   823 
   824 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   825 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   826 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   827 
   828 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   829 changed order of proof goals in instance proofs.
   830 
   831 * The transitivity reasoner for partial and linear orders is set up
   832 for classes "order" and "linorder".  Instances of the reasoner are available
   833 in all contexts importing or interpreting the corresponding locales.
   834 Method "order" invokes the reasoner separately; the reasoner
   835 is also integrated with the Simplifier as a solver.  Diagnostic
   836 command 'print_orders' shows the available instances of the reasoner
   837 in the current context.
   838 
   839 * Localized monotonicity predicate in theory "Orderings"; integrated
   840 lemmas max_of_mono and min_of_mono with this predicate.
   841 INCOMPATIBILITY.
   842 
   843 * Formulation of theorem "dense" changed slightly due to integration
   844 with new class dense_linear_order.
   845 
   846 * Uniform lattice theory development in HOL.
   847 
   848     constants "meet" and "join" now named "inf" and "sup"
   849     constant "Meet" now named "Inf"
   850 
   851     classes "meet_semilorder" and "join_semilorder" now named
   852       "lower_semilattice" and "upper_semilattice"
   853     class "lorder" now named "lattice"
   854     class "comp_lat" now named "complete_lattice"
   855 
   856     Instantiation of lattice classes allows explicit definitions
   857     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   858 
   859   INCOMPATIBILITY.  Theorem renames:
   860 
   861     meet_left_le            ~> inf_le1
   862     meet_right_le           ~> inf_le2
   863     join_left_le            ~> sup_ge1
   864     join_right_le           ~> sup_ge2
   865     meet_join_le            ~> inf_sup_ord
   866     le_meetI                ~> le_infI
   867     join_leI                ~> le_supI
   868     le_meet                 ~> le_inf_iff
   869     le_join                 ~> ge_sup_conv
   870     meet_idempotent         ~> inf_idem
   871     join_idempotent         ~> sup_idem
   872     meet_comm               ~> inf_commute
   873     join_comm               ~> sup_commute
   874     meet_leI1               ~> le_infI1
   875     meet_leI2               ~> le_infI2
   876     le_joinI1               ~> le_supI1
   877     le_joinI2               ~> le_supI2
   878     meet_assoc              ~> inf_assoc
   879     join_assoc              ~> sup_assoc
   880     meet_left_comm          ~> inf_left_commute
   881     meet_left_idempotent    ~> inf_left_idem
   882     join_left_comm          ~> sup_left_commute
   883     join_left_idempotent    ~> sup_left_idem
   884     meet_aci                ~> inf_aci
   885     join_aci                ~> sup_aci
   886     le_def_meet             ~> le_iff_inf
   887     le_def_join             ~> le_iff_sup
   888     join_absorp2            ~> sup_absorb2
   889     join_absorp1            ~> sup_absorb1
   890     meet_absorp1            ~> inf_absorb1
   891     meet_absorp2            ~> inf_absorb2
   892     meet_join_absorp        ~> inf_sup_absorb
   893     join_meet_absorp        ~> sup_inf_absorb
   894     distrib_join_le         ~> distrib_sup_le
   895     distrib_meet_le         ~> distrib_inf_le
   896 
   897     add_meet_distrib_left   ~> add_inf_distrib_left
   898     add_join_distrib_left   ~> add_sup_distrib_left
   899     is_join_neg_meet        ~> is_join_neg_inf
   900     is_meet_neg_join        ~> is_meet_neg_sup
   901     add_meet_distrib_right  ~> add_inf_distrib_right
   902     add_join_distrib_right  ~> add_sup_distrib_right
   903     add_meet_join_distribs  ~> add_sup_inf_distribs
   904     join_eq_neg_meet        ~> sup_eq_neg_inf
   905     meet_eq_neg_join        ~> inf_eq_neg_sup
   906     add_eq_meet_join        ~> add_eq_inf_sup
   907     meet_0_imp_0            ~> inf_0_imp_0
   908     join_0_imp_0            ~> sup_0_imp_0
   909     meet_0_eq_0             ~> inf_0_eq_0
   910     join_0_eq_0             ~> sup_0_eq_0
   911     neg_meet_eq_join        ~> neg_inf_eq_sup
   912     neg_join_eq_meet        ~> neg_sup_eq_inf
   913     join_eq_if              ~> sup_eq_if
   914 
   915     mono_meet               ~> mono_inf
   916     mono_join               ~> mono_sup
   917     meet_bool_eq            ~> inf_bool_eq
   918     join_bool_eq            ~> sup_bool_eq
   919     meet_fun_eq             ~> inf_fun_eq
   920     join_fun_eq             ~> sup_fun_eq
   921     meet_set_eq             ~> inf_set_eq
   922     join_set_eq             ~> sup_set_eq
   923     meet1_iff               ~> inf1_iff
   924     meet2_iff               ~> inf2_iff
   925     meet1I                  ~> inf1I
   926     meet2I                  ~> inf2I
   927     meet1D1                 ~> inf1D1
   928     meet2D1                 ~> inf2D1
   929     meet1D2                 ~> inf1D2
   930     meet2D2                 ~> inf2D2
   931     meet1E                  ~> inf1E
   932     meet2E                  ~> inf2E
   933     join1_iff               ~> sup1_iff
   934     join2_iff               ~> sup2_iff
   935     join1I1                 ~> sup1I1
   936     join2I1                 ~> sup2I1
   937     join1I1                 ~> sup1I1
   938     join2I2                 ~> sup1I2
   939     join1CI                 ~> sup1CI
   940     join2CI                 ~> sup2CI
   941     join1E                  ~> sup1E
   942     join2E                  ~> sup2E
   943 
   944     is_meet_Meet            ~> is_meet_Inf
   945     Meet_bool_def           ~> Inf_bool_def
   946     Meet_fun_def            ~> Inf_fun_def
   947     Meet_greatest           ~> Inf_greatest
   948     Meet_lower              ~> Inf_lower
   949     Meet_set_def            ~> Inf_set_def
   950 
   951     Sup_def                 ~> Sup_Inf
   952     Sup_bool_eq             ~> Sup_bool_def
   953     Sup_fun_eq              ~> Sup_fun_def
   954     Sup_set_eq              ~> Sup_set_def
   955 
   956     listsp_meetI            ~> listsp_infI
   957     listsp_meet_eq          ~> listsp_inf_eq
   958 
   959     meet_min                ~> inf_min
   960     join_max                ~> sup_max
   961 
   962 * Added syntactic class "size"; overloaded constant "size" now has
   963 type "'a::size ==> bool"
   964 
   965 * Internal reorganisation of `size' of datatypes: size theorems
   966 "foo.size" are no longer subsumed by "foo.simps" (but are still
   967 simplification rules by default!); theorems "prod.size" now named
   968 "*.size".
   969 
   970 * Class "div" now inherits from class "times" rather than "type".
   971 INCOMPATIBILITY.
   972 
   973 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   974 Linorder etc.  have disappeared; operations defined in terms of
   975 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   976 
   977 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   978 
   979 * HOL-Word: New extensive library and type for generic, fixed size
   980 machine words, with arithemtic, bit-wise, shifting and rotating
   981 operations, reflection into int, nat, and bool lists, automation for
   982 linear arithmetic (by automatic reflection into nat or int), including
   983 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   984 arithmetic type classes, supporting automatic simplification of
   985 numerals on all operations.
   986 
   987 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   988 
   989 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   990 
   991 * Code generator library theories:
   992   - Code_Integer represents HOL integers by big integer literals in target
   993     languages.
   994   - Code_Char represents HOL characters by character literals in target
   995     languages.
   996   - Code_Char_chr like Code_Char, but also offers treatment of character
   997     codes; includes Code_Integer.
   998   - Executable_Set allows to generate code for finite sets using lists.
   999   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1000     denominator).
  1001   - Executable_Real implements a subset of real numbers, namly those
  1002     representable by rational numbers.
  1003   - Efficient_Nat implements natural numbers by integers, which in general will
  1004     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1005     includes Code_Integer.
  1006   - Code_Index provides an additional datatype index which is mapped to
  1007     target-language built-in integers.
  1008   - Code_Message provides an additional datatype message_string} which is isomorphic to
  1009     strings; messages are mapped to target-language strings.
  1010 
  1011 * New package for inductive predicates
  1012 
  1013   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1014 
  1015     inductive
  1016       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1017       for z_1 :: U_1 and ... and z_n :: U_m
  1018     where
  1019       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1020     | ...
  1021 
  1022   with full support for type-inference, rather than
  1023 
  1024     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1025 
  1026     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1027     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1028 
  1029     inductive "s z_1 ... z_m"
  1030     intros
  1031       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1032       ...
  1033 
  1034   For backward compatibility, there is a wrapper allowing inductive
  1035   sets to be defined with the new package via
  1036 
  1037     inductive_set
  1038       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1039       for z_1 :: U_1 and ... and z_n :: U_m
  1040     where
  1041       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1042     | ...
  1043 
  1044   or
  1045 
  1046     inductive_set
  1047       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1048       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1049       for z_1 :: U_1 and ... and z_n :: U_m
  1050     where
  1051       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1052     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1053     | ...
  1054 
  1055   if the additional syntax "p ..." is required.
  1056 
  1057   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1058   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1059 
  1060   INCOMPATIBILITIES:
  1061 
  1062   - Since declaration and definition of inductive sets or predicates
  1063     is no longer separated, abbreviations involving the newly
  1064     introduced sets or predicates must be specified together with the
  1065     introduction rules after the 'where' keyword (see above), rather
  1066     than before the actual inductive definition.
  1067 
  1068   - The variables in induction and elimination rules are now
  1069     quantified in the order of their occurrence in the introduction
  1070     rules, rather than in alphabetical order. Since this may break
  1071     some proofs, these proofs either have to be repaired, e.g. by
  1072     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1073     statements of the form
  1074 
  1075       case (rule_i a_i_1 ... a_i_{k_i})
  1076 
  1077     or the old order of quantification has to be restored by explicitly adding
  1078     meta-level quantifiers in the introduction rules, i.e.
  1079 
  1080       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1081 
  1082   - The format of the elimination rules is now
  1083 
  1084       p z_1 ... z_m x_1 ... x_n ==>
  1085         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1086         ==> ... ==> P
  1087 
  1088     for predicates and
  1089 
  1090       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1091         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1092         ==> ... ==> P
  1093 
  1094     for sets rather than
  1095 
  1096       x : s z_1 ... z_m ==>
  1097         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1098         ==> ... ==> P
  1099 
  1100     This may require terms in goals to be expanded to n-tuples
  1101     (e.g. using case_tac or simplification with the split_paired_all
  1102     rule) before the above elimination rule is applicable.
  1103 
  1104   - The elimination or case analysis rules for (mutually) inductive
  1105     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1106     list of rules "p_1_..._p_k.elims" is no longer available.
  1107 
  1108 * New package "function"/"fun" for general recursive functions,
  1109 supporting mutual and nested recursion, definitions in local contexts,
  1110 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1111 for small examples, and the separate tutorial on the function
  1112 package. The old recdef "package" is still available as before, but
  1113 users are encouraged to use the new package.
  1114 
  1115 * Method "lexicographic_order" automatically synthesizes termination
  1116 relations as lexicographic combinations of size measures. 
  1117 
  1118 * Case-expressions allow arbitrary constructor-patterns (including
  1119 "_") and take their order into account, like in functional
  1120 programming.  Internally, this is translated into nested
  1121 case-expressions; missing cases are added and mapped to the predefined
  1122 constant "undefined". In complicated cases printing may no longer show
  1123 the original input but the internal form. Lambda-abstractions allow
  1124 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1125 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1126 variable.
  1127 
  1128 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1129 is an abbreviation for "of_nat :: nat => int". The simplification
  1130 rules for "of_nat" have been changed to work like "int" did
  1131 previously.  Potential INCOMPATIBILITY:
  1132   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1133   - of_nat_diff and of_nat_mult are no longer default simp rules
  1134 
  1135 * Method "algebra" solves polynomial equations over (semi)rings using
  1136 Groebner bases. The (semi)ring structure is defined by locales and the
  1137 tool setup depends on that generic context. Installing the method for
  1138 a specific type involves instantiating the locale and possibly adding
  1139 declarations for computation on the coefficients.  The method is
  1140 already instantiated for natural numbers and for the axiomatic class
  1141 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1142 CALCULEMUS 2007 for the general principles underlying this
  1143 architecture of context-aware proof-tools.
  1144 
  1145 * Method "ferrack" implements quantifier elimination over
  1146 special-purpose dense linear orders using locales (analogous to
  1147 "algebra"). The method is already installed for class
  1148 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1149 rat, etc.
  1150 
  1151 * Former constant "List.op @" now named "List.append".  Use ML
  1152 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1153 circumvent possible incompatibilities when working on ML level.
  1154 
  1155 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1156 
  1157 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1158 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1159 
  1160 * New syntax for Haskell-like list comprehension (input only), eg.
  1161 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1162 
  1163 * The special syntax for function "filter" has changed from [x :
  1164 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1165 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1166 
  1167 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1168 defined on nat only, as an abbreviation for [a..<Suc b]
  1169 INCOMPATIBILITY.
  1170 
  1171 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1172 
  1173 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1174 
  1175 * New lemma collection field_simps (an extension of ring_simps) for
  1176 manipulating (in)equations involving division. Multiplies with all
  1177 denominators that can be proved to be non-zero (in equations) or
  1178 positive/negative (in inequations).
  1179 
  1180 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1181 have been improved and renamed to ring_simps, group_simps and
  1182 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1183 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1184 
  1185 * Theory Library/Commutative_Ring: switched from recdef to function
  1186 package; constants add, mul, pow now curried.  Infix syntax for
  1187 algebraic operations.
  1188 
  1189 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1190 INCOMPATIBILITY.
  1191 
  1192 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1193 INCOMPATIBILITY.
  1194 
  1195 * HOL/records: generalised field-update to take a function on the
  1196 field rather than the new value: r(|A := x|) is translated to A_update
  1197 (K x) r The K-combinator that is internally used is called K_record.
  1198 INCOMPATIBILITY: Usage of the plain update functions has to be
  1199 adapted.
  1200  
  1201 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1202 * x = 0, which are required for a semiring.  Richer structures do not
  1203 inherit from semiring_0 anymore, because this property is a theorem
  1204 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1205 there is more to prove, but this is mostly trivial.
  1206 
  1207 * Class "recpower" is generalized to arbitrary monoids, not just
  1208 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1209 commutativity or semiring properties additionally.
  1210 
  1211 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1212 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1213 better use 'abbreviation'.
  1214 
  1215 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1216 
  1217 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1218 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1219 significant changes for setting up numeral syntax for types:
  1220   - New constants Numeral.pred and Numeral.succ instead
  1221       of former Numeral.bin_pred and Numeral.bin_succ.
  1222   - Use integer operations instead of bin_add, bin_mult and so on.
  1223   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1224   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1225 
  1226 See src/HOL/Integ/IntArith.thy for an example setup.
  1227 
  1228 * Command 'normal_form' computes the normal form of a term that may
  1229 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1230 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1231 heavy-duty computations because the functions are compiled to ML
  1232 first.  Correspondingly, a method "normalization" is provided.  See
  1233 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1234 
  1235 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1236 25 like -->); output depends on the "iff" print_mode, the default is
  1237 "A = B" (with priority 50).
  1238 
  1239 * Relations less (<) and less_eq (<=) are also available on type bool.
  1240 Modified syntax to disallow nesting without explicit parentheses,
  1241 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1242 INCOMPATIBILITY.
  1243 
  1244 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1245 
  1246 * Relation composition operator "op O" now has precedence 75 and binds
  1247 stronger than union and intersection. INCOMPATIBILITY.
  1248 
  1249 * The old set interval syntax "{m..n(}" (and relatives) has been
  1250 removed.  Use "{m..<n}" (and relatives) instead.
  1251 
  1252 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1253 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1254 ``declare [[simproc del: neq]]''.
  1255 
  1256 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1257 True/False.
  1258 
  1259 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1260 
  1261 * Theorem setsum_mult renamed to setsum_right_distrib.
  1262 
  1263 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1264 ``rule'' method.
  1265 
  1266 * Reimplemented methods "sat" and "satx", with several improvements:
  1267 goals no longer need to be stated as "<prems> ==> False", equivalences
  1268 (i.e. "=" on type bool) are handled, variable names of the form
  1269 "lit_<n>" are no longer reserved, significant speedup.
  1270 
  1271 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1272 zChaff is still supported as well.
  1273 
  1274 * 'inductive' and 'datatype': provide projections of mutual rules,
  1275 bundled as foo_bar.inducts;
  1276 
  1277 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1278 Library.
  1279 
  1280 * Library: moved theory Accessible_Part to main HOL.
  1281 
  1282 * Library: added theory Coinductive_List of potentially infinite lists
  1283 as greatest fixed-point.
  1284 
  1285 * Library: added theory AssocList which implements (finite) maps as
  1286 association lists.
  1287 
  1288 * Method "evaluation" solves goals (i.e. a boolean expression)
  1289 efficiently by compiling it to ML.  The goal is "proved" (via an
  1290 oracle) if it evaluates to True.
  1291 
  1292 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1293 also when invoked by the simplifier.  This results in the Simplifier
  1294 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1295 Configuration option fast_arith_split_limit=0 recovers the old
  1296 behavior.
  1297 
  1298 * Support for hex (0x20) and binary (0b1001) numerals.
  1299 
  1300 * New method: reify eqs (t), where eqs are equations for an
  1301 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1302 parameter, computes a term s::'b and a list xs::'a list and proves the
  1303 theorem I xs s = t. This is also known as reification or quoting. The
  1304 resulting theorem is applied to the subgoal to substitute t with I xs
  1305 s.  If t is omitted, the subgoal itself is reified.
  1306 
  1307 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1308 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1309 where f is supposed to be a computable function (in the sense of code
  1310 generattion). The method uses reify to compute s and xs as above then
  1311 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1312 r and finally gets the theorem t = r, which is again applied to the
  1313 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1314 
  1315 * Reflection: Automatic reification now handels binding, an example is
  1316 available in src/HOL/ex/ReflectionEx.thy
  1317 
  1318 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1319 command 'statespace' that is similar to 'record', but introduces an
  1320 abstract specification based on the locale infrastructure instead of
  1321 HOL types.  This leads to extra flexibility in composing state spaces,
  1322 in particular multiple inheritance and renaming of components.
  1323 
  1324 
  1325 *** HOL-Complex ***
  1326 
  1327 * Hyperreal: Functions root and sqrt are now defined on negative real
  1328 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1329 Nonnegativity side conditions have been removed from many lemmas, so
  1330 that more subgoals may now be solved by simplification; potential
  1331 INCOMPATIBILITY.
  1332 
  1333 * Real: new type classes formalize real normed vector spaces and
  1334 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1335 and norm :: 'a => real.
  1336 
  1337 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1338 reals into other types. The overloaded constant Reals :: 'a set is now
  1339 defined as range of_real; potential INCOMPATIBILITY.
  1340 
  1341 * Real: proper support for ML code generation, including 'quickcheck'.
  1342 Reals are implemented as arbitrary precision rationals.
  1343 
  1344 * Hyperreal: Several constants that previously worked only for the
  1345 reals have been generalized, so they now work over arbitrary vector
  1346 spaces. Type annotations may need to be added in some cases; potential
  1347 INCOMPATIBILITY.
  1348 
  1349   Infinitesimal  :: ('a::real_normed_vector) star set
  1350   HFinite        :: ('a::real_normed_vector) star set
  1351   HInfinite      :: ('a::real_normed_vector) star set
  1352   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1353   monad          :: ('a::real_normed_vector) star => 'a star set
  1354   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1355   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1356   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1357   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1358   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1359   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1360   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1361   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1362   sgn            :: 'a::real_normed_vector => 'a
  1363   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1364 
  1365 * Complex: Some complex-specific constants are now abbreviations for
  1366 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1367 hnorm.  Other constants have been entirely removed in favor of the
  1368 polymorphic versions (INCOMPATIBILITY):
  1369 
  1370   approx        <-- capprox
  1371   HFinite       <-- CFinite
  1372   HInfinite     <-- CInfinite
  1373   Infinitesimal <-- CInfinitesimal
  1374   monad         <-- cmonad
  1375   galaxy        <-- cgalaxy
  1376   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1377   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1378   (ns)deriv     <-- (ns)cderiv
  1379 
  1380 
  1381 *** HOL-Algebra ***
  1382 
  1383 * Formalisation of ideals and the quotient construction over rings.
  1384 
  1385 * Order and lattice theory no longer based on records.
  1386 INCOMPATIBILITY.
  1387 
  1388 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1389 greatest_closed.  INCOMPATIBILITY.
  1390 
  1391 * Method algebra is now set up via an attribute.  For examples see
  1392 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1393 of algebraic structures.
  1394 
  1395 * Renamed theory CRing to Ring.
  1396 
  1397 
  1398 *** HOL-Nominal ***
  1399 
  1400 * Substantial, yet incomplete support for nominal datatypes (binding
  1401 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1402 src/HOL/Nominal/Examples.  Prospective users should consult
  1403 http://isabelle.in.tum.de/nominal/
  1404 
  1405 
  1406 *** ML ***
  1407 
  1408 * ML basics: just one true type int, which coincides with IntInf.int
  1409 (even on SML/NJ).
  1410 
  1411 * ML within Isar: antiquotations allow to embed statically-checked
  1412 formal entities in the source, referring to the context available at
  1413 compile-time.  For example:
  1414 
  1415 ML {* @{sort "{zero,one}"} *}
  1416 ML {* @{typ "'a => 'b"} *}
  1417 ML {* @{term "%x. x"} *}
  1418 ML {* @{prop "x == y"} *}
  1419 ML {* @{ctyp "'a => 'b"} *}
  1420 ML {* @{cterm "%x. x"} *}
  1421 ML {* @{cprop "x == y"} *}
  1422 ML {* @{thm asm_rl} *}
  1423 ML {* @{thms asm_rl} *}
  1424 ML {* @{type_name c} *}
  1425 ML {* @{type_syntax c} *}
  1426 ML {* @{const_name c} *}
  1427 ML {* @{const_syntax c} *}
  1428 ML {* @{context} *}
  1429 ML {* @{theory} *}
  1430 ML {* @{theory Pure} *}
  1431 ML {* @{theory_ref} *}
  1432 ML {* @{theory_ref Pure} *}
  1433 ML {* @{simpset} *}
  1434 ML {* @{claset} *}
  1435 ML {* @{clasimpset} *}
  1436 
  1437 The same works for sources being ``used'' within an Isar context.
  1438 
  1439 * ML in Isar: improved error reporting; extra verbosity with
  1440 ML_Context.trace enabled.
  1441 
  1442 * Pure/General/table.ML: the join operations now works via exceptions
  1443 DUP/SAME instead of type option. This is simpler in simple cases, and
  1444 admits slightly more efficient complex applications.
  1445 
  1446 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1447 use Context.generic instead of just theory.
  1448 
  1449 * Pure: datatype Context.generic joins theory/Proof.context and
  1450 provides some facilities for code that works in either kind of
  1451 context, notably GenericDataFun for uniform theory and proof data.
  1452 
  1453 * Pure: simplified internal attribute type, which is now always
  1454 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1455 local (Proof.context) attributes have been discontinued, while
  1456 minimizing code duplication. Thm.rule_attribute and
  1457 Thm.declaration_attribute build canonical attributes; see also structure
  1458 Context for further operations on Context.generic, notably
  1459 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1460 declarations and definitions.
  1461 
  1462 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1463 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1464 init only required for impure data. INCOMPATIBILITY: empty really need
  1465 to be empty (no dependencies on theory content!)
  1466 
  1467 * Pure/kernel: consts certification ignores sort constraints given in
  1468 signature declarations. (This information is not relevant to the
  1469 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1470 potential INCOMPATIBILITY.
  1471 
  1472 * Pure: axiomatic type classes are now purely definitional, with
  1473 explicit proofs of class axioms and super class relations performed
  1474 internally. See Pure/axclass.ML for the main internal interfaces --
  1475 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1476 AxClass.axiomatize_class/classrel/arity supersede
  1477 Sign.add_classes/classrel/arities.
  1478 
  1479 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1480 global/local versions on theory vs. Proof.context have been
  1481 discontinued; Attrib.syntax and Method.syntax have been adapted
  1482 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1483 attributes, methods, etc.
  1484 
  1485 * Pure: several functions of signature "... -> theory -> theory * ..."
  1486 have been reoriented to "... -> theory -> ... * theory" in order to
  1487 allow natural usage in combination with the ||>, ||>>, |-> and
  1488 fold_map combinators.
  1489 
  1490 * Pure: official theorem names (closed derivations) and additional
  1491 comments (tags) are now strictly separate.  Name hints -- which are
  1492 maintained as tags -- may be attached any time without affecting the
  1493 derivation.
  1494 
  1495 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1496 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1497 achieve the old behaviour.
  1498 
  1499 * Pure: the "Goal" constant is now called "prop", supporting a
  1500 slightly more general idea of ``protecting'' meta-level rule
  1501 statements.
  1502 
  1503 * Pure: Logic.(un)varify only works in a global context, which is now
  1504 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1505 Logic.legacy_(un)varify as temporary workaround.
  1506 
  1507 * Pure: structure Name provides scalable operations for generating
  1508 internal variable names, notably Name.variants etc.  This replaces
  1509 some popular functions from term.ML:
  1510 
  1511   Term.variant		->  Name.variant
  1512   Term.variantlist	->  Name.variant_list
  1513   Term.invent_names	->  Name.invent_list
  1514 
  1515 Note that low-level renaming rarely occurs in new code -- operations
  1516 from structure Variable are used instead (see below).
  1517 
  1518 * Pure: structure Variable provides fundamental operations for proper
  1519 treatment of fixed/schematic variables in a context.  For example,
  1520 Variable.import introduces fixes for schematics of given facts and
  1521 Variable.export reverses the effect (up to renaming) -- this replaces
  1522 various freeze_thaw operations.
  1523 
  1524 * Pure: structure Goal provides simple interfaces for
  1525 init/conclude/finish and tactical prove operations (replacing former
  1526 Tactic.prove).  Goal.prove is the canonical way to prove results
  1527 within a given context; Goal.prove_global is a degraded version for
  1528 theory level goals, including a global Drule.standard.  Note that
  1529 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1530 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1531 in a locale context).
  1532 
  1533 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1534 and type checking (Syntax.check_term etc.), with common combinations
  1535 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1536 which are considered legacy and await removal.
  1537 
  1538 * Pure/Syntax: generic interfaces for type unchecking
  1539 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1540 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1541 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1542 available for convenience, but refer to the very same operations using
  1543 a mere theory instead of a full context.
  1544 
  1545 * Isar: simplified treatment of user-level errors, using exception
  1546 ERROR of string uniformly.  Function error now merely raises ERROR,
  1547 without any side effect on output channels.  The Isar toplevel takes
  1548 care of proper display of ERROR exceptions.  ML code may use plain
  1549 handle/can/try; cat_error may be used to concatenate errors like this:
  1550 
  1551   ... handle ERROR msg => cat_error msg "..."
  1552 
  1553 Toplevel ML code (run directly or through the Isar toplevel) may be
  1554 embedded into the Isar toplevel with exception display/debug like
  1555 this:
  1556 
  1557   Isar.toplevel (fn () => ...)
  1558 
  1559 INCOMPATIBILITY, removed special transform_error facilities, removed
  1560 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1561 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1562 -- use plain ERROR instead.
  1563 
  1564 * Isar: theory setup now has type (theory -> theory), instead of a
  1565 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1566 
  1567 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1568 ProofContext.debug/verbose flags.
  1569 
  1570 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1571 theory before entering a proof state.  Transactions now always see a
  1572 quasi-functional intermediate checkpoint, both in interactive and
  1573 batch mode.
  1574 
  1575 * Isar: simplified interfaces for outer syntax.  Renamed
  1576 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1577 OuterSyntax.add_parsers -- this functionality is now included in
  1578 OuterSyntax.command etc.  INCOMPATIBILITY.
  1579 
  1580 * Simplifier: the simpset of a running simplification process now
  1581 contains a proof context (cf. Simplifier.the_context), which is the
  1582 very context that the initial simpset has been retrieved from (by
  1583 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1584 (solver, looper etc.) may depend on arbitrary proof data.
  1585 
  1586 * Simplifier.inherit_context inherits the proof context (plus the
  1587 local bounds) of the current simplification process; any simproc
  1588 etc. that calls the Simplifier recursively should do this!  Removed
  1589 former Simplifier.inherit_bounds, which is already included here --
  1590 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1591 specify an explicit context using Simplifier.context/theory_context.
  1592 
  1593 * Simplifier/Classical Reasoner: more abstract interfaces
  1594 change_simpset/claset for modifying the simpset/claset reference of a
  1595 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1596 INCOMPATIBILITY.
  1597 
  1598 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1599 "Trueprop" etc.
  1600 
  1601 
  1602 *** System ***
  1603 
  1604 * settings: the default heap location within ISABELLE_HOME_USER now
  1605 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1606 Isabelle installations.
  1607 
  1608 * isabelle-process: option -S (secure mode) disables some critical
  1609 operations, notably runtime compilation and evaluation of ML source
  1610 code.
  1611 
  1612 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1613 
  1614 * Support for parallel execution, using native multicore support of
  1615 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1616 independent theories, according to the given theory header
  1617 specifications. The maximum number of worker threads is specified via
  1618 usedir option -M or the "max-threads" setting in Proof General. A
  1619 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1620 to 6 on a 8-core machine.  User-code needs to observe certain
  1621 guidelines for thread-safe programming, see appendix A in the Isar
  1622 Implementation manual.
  1623 
  1624 
  1625 
  1626 New in Isabelle2005 (October 2005)
  1627 ----------------------------------
  1628 
  1629 *** General ***
  1630 
  1631 * Theory headers: the new header syntax for Isar theories is
  1632 
  1633   theory <name>
  1634   imports <theory1> ... <theoryN>
  1635   uses <file1> ... <fileM>
  1636   begin
  1637 
  1638 where the 'uses' part is optional.  The previous syntax
  1639 
  1640   theory <name> = <theory1> + ... + <theoryN>:
  1641 
  1642 will disappear in the next release.  Use isatool fixheaders to convert
  1643 existing theory files.  Note that there is no change in ancient
  1644 non-Isar theories now, but these will disappear soon.
  1645 
  1646 * Theory loader: parent theories can now also be referred to via
  1647 relative and absolute paths.
  1648 
  1649 * Command 'find_theorems' searches for a list of criteria instead of a
  1650 list of constants. Known criteria are: intro, elim, dest, name:string,
  1651 simp:term, and any term. Criteria can be preceded by '-' to select
  1652 theorems that do not match. Intro, elim, dest select theorems that
  1653 match the current goal, name:s selects theorems whose fully qualified
  1654 name contain s, and simp:term selects all simplification rules whose
  1655 lhs match term.  Any other term is interpreted as pattern and selects
  1656 all theorems matching the pattern. Available in ProofGeneral under
  1657 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1658 
  1659   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1660 
  1661 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1662 matching the current goal as introduction rule and not having "HOL."
  1663 in their name (i.e. not being defined in theory HOL).
  1664 
  1665 * Command 'thms_containing' has been discontinued in favour of
  1666 'find_theorems'; INCOMPATIBILITY.
  1667 
  1668 * Communication with Proof General is now 8bit clean, which means that
  1669 Unicode text in UTF-8 encoding may be used within theory texts (both
  1670 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1671 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1672 
  1673   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1674   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1675 
  1676 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1677 Classical Reasoner.  Typical big applications run around 2 times
  1678 faster.
  1679 
  1680 
  1681 *** Document preparation ***
  1682 
  1683 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1684 of raw sources.  Only those symbols that do not require additional
  1685 LaTeX packages (depending on comments in isabellesym.sty) are
  1686 displayed properly, everything else is left verbatim.  isatool display
  1687 and isatool print are used as front ends (these are subject to the
  1688 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1689 
  1690 * Command tags control specific markup of certain regions of text,
  1691 notably folding and hiding.  Predefined tags include "theory" (for
  1692 theory begin and end), "proof" for proof commands, and "ML" for
  1693 commands involving ML code; the additional tags "visible" and
  1694 "invisible" are unused by default.  Users may give explicit tag
  1695 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1696 interpretation of tags is determined by the LaTeX job during document
  1697 preparation: see option -V of isatool usedir, or options -n and -t of
  1698 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1699 \isadroptag.
  1700 
  1701 Several document versions may be produced at the same time via isatool
  1702 usedir (the generated index.html will link all of them).  Typical
  1703 specifications include ''-V document=theory,proof,ML'' to present
  1704 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1705 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1706 these parts without any formal replacement text.  The Isabelle site
  1707 default settings produce ''document'' and ''outline'' versions as
  1708 specified above.
  1709 
  1710 * Several new antiquotations:
  1711 
  1712   @{term_type term} prints a term with its type annotated;
  1713 
  1714   @{typeof term} prints the type of a term;
  1715 
  1716   @{const const} is the same as @{term const}, but checks that the
  1717   argument is a known logical constant;
  1718 
  1719   @{term_style style term} and @{thm_style style thm} print a term or
  1720   theorem applying a "style" to it
  1721 
  1722   @{ML text}
  1723 
  1724 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1725 definitions, equations, inequations etc., 'concl' printing only the
  1726 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1727 to print the specified premise.  TermStyle.add_style provides an ML
  1728 interface for introducing further styles.  See also the "LaTeX Sugar"
  1729 document practical applications.  The ML antiquotation prints
  1730 type-checked ML expressions verbatim.
  1731 
  1732 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1733 and 'text' support optional locale specification '(in loc)', which
  1734 specifies the default context for interpreting antiquotations.  For
  1735 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1736 
  1737 * Option 'locale=NAME' of antiquotations specifies an alternative
  1738 context interpreting the subsequent argument.  For example: @{thm
  1739 [locale=lattice] inf_assoc}.
  1740 
  1741 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1742 a proof context.
  1743 
  1744 * Proper output of antiquotations for theory commands involving a
  1745 proof context (such as 'locale' or 'theorem (in loc) ...').
  1746 
  1747 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1748 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1749 
  1750 * isatool usedir: new option -C (default true) controls whether option
  1751 -D should include a copy of the original document directory; -C false
  1752 prevents unwanted effects such as copying of administrative CVS data.
  1753 
  1754 
  1755 *** Pure ***
  1756 
  1757 * Considerably improved version of 'constdefs' command.  Now performs
  1758 automatic type-inference of declared constants; additional support for
  1759 local structure declarations (cf. locales and HOL records), see also
  1760 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1761 sequential dependencies of definitions within a single 'constdefs'
  1762 section; moreover, the declared name needs to be an identifier.  If
  1763 all fails, consider to fall back on 'consts' and 'defs' separately.
  1764 
  1765 * Improved indexed syntax and implicit structures.  First of all,
  1766 indexed syntax provides a notational device for subscripted
  1767 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1768 expressions.  Secondly, in a local context with structure
  1769 declarations, number indexes \<^sub>n or the empty index (default
  1770 number 1) refer to a certain fixed variable implicitly; option
  1771 show_structs controls printing of implicit structures.  Typical
  1772 applications of these concepts involve record types and locales.
  1773 
  1774 * New command 'no_syntax' removes grammar declarations (and
  1775 translations) resulting from the given syntax specification, which is
  1776 interpreted in the same manner as for the 'syntax' command.
  1777 
  1778 * 'Advanced' translation functions (parse_translation etc.) may depend
  1779 on the signature of the theory context being presently used for
  1780 parsing/printing, see also isar-ref manual.
  1781 
  1782 * Improved 'oracle' command provides a type-safe interface to turn an
  1783 ML expression of type theory -> T -> term into a primitive rule of
  1784 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1785 is already included here); see also FOL/ex/IffExample.thy;
  1786 INCOMPATIBILITY.
  1787 
  1788 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1789 before); "cI" is no longer bound, use "c.intro" instead.
  1790 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1791 axclasses vs. locales.
  1792 
  1793 * Improved internal renaming of symbolic identifiers -- attach primes
  1794 instead of base 26 numbers.
  1795 
  1796 * New flag show_question_marks controls printing of leading question
  1797 marks in schematic variable names.
  1798 
  1799 * In schematic variable names, *any* symbol following \<^isub> or
  1800 \<^isup> is now treated as part of the base name.  For example, the
  1801 following works without printing of awkward ".0" indexes:
  1802 
  1803   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1804     by simp
  1805 
  1806 * Inner syntax includes (*(*nested*) comments*).
  1807 
  1808 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1809 annotations as "(00...)".
  1810 
  1811 * Clear separation of logical types and nonterminals, where the latter
  1812 may only occur in 'syntax' specifications or type abbreviations.
  1813 Before that distinction was only partially implemented via type class
  1814 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1815 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1816 exotic syntax specifications may require further adaption
  1817 (e.g. Cube/Cube.thy).
  1818 
  1819 * Removed obsolete type class "logic", use the top sort {} instead.
  1820 Note that non-logical types should be declared as 'nonterminals'
  1821 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1822 specifications.
  1823 
  1824 * Attributes 'induct' and 'cases': type or set names may now be
  1825 locally fixed variables as well.
  1826 
  1827 * Simplifier: can now control the depth to which conditional rewriting
  1828 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1829 Limit.
  1830 
  1831 * Simplifier: simplification procedures may now take the current
  1832 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1833 interface), which is very useful for calling the Simplifier
  1834 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1835 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1836 low-level mk_simproc no longer applies Logic.varify internally, to
  1837 allow for use in a context of fixed variables.
  1838 
  1839 * thin_tac now works even if the assumption being deleted contains !!
  1840 or ==>.  More generally, erule now works even if the major premise of
  1841 the elimination rule contains !! or ==>.
  1842 
  1843 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1844 
  1845 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1846 from Pure, which contains all common declarations already.  Both
  1847 theories are defined via plain Isabelle/Isar .thy files.
  1848 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1849 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1850 use isatool fixcpure to adapt your theory and ML sources.
  1851 
  1852 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1853 selections of theorems in named facts via index ranges.
  1854 
  1855 * 'print_theorems': in theory mode, really print the difference
  1856 wrt. the last state (works for interactive theory development only),
  1857 in proof mode print all local facts (cf. 'print_facts');
  1858 
  1859 * 'hide': option '(open)' hides only base names.
  1860 
  1861 * More efficient treatment of intermediate checkpoints in interactive
  1862 theory development.
  1863 
  1864 * Code generator is now invoked via code_module (incremental code
  1865 generation) and code_library (modular code generation, ML structures
  1866 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1867 must be quoted when used as identifiers.
  1868 
  1869 * New 'value' command for reading, evaluating and printing terms using
  1870 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1871 quoted when used as identifier.
  1872 
  1873 
  1874 *** Locales ***
  1875 
  1876 * New commands for the interpretation of locale expressions in
  1877 theories (1), locales (2) and proof contexts (3).  These generate
  1878 proof obligations from the expression specification.  After the
  1879 obligations have been discharged, theorems of the expression are added
  1880 to the theory, target locale or proof context.  The synopsis of the
  1881 commands is a follows:
  1882 
  1883   (1) interpretation expr inst
  1884   (2) interpretation target < expr
  1885   (3) interpret expr inst
  1886 
  1887 Interpretation in theories and proof contexts require a parameter
  1888 instantiation of terms from the current context.  This is applied to
  1889 specifications and theorems of the interpreted expression.
  1890 Interpretation in locales only permits parameter renaming through the
  1891 locale expression.  Interpretation is smart in that interpretations
  1892 that are active already do not occur in proof obligations, neither are
  1893 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1894 inspect active interpretations of a particular locale.  For details,
  1895 see the Isar Reference manual.  Examples can be found in
  1896 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1897 
  1898 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1899 'interpret' instead.
  1900 
  1901 * New context element 'constrains' for adding type constraints to
  1902 parameters.
  1903 
  1904 * Context expressions: renaming of parameters with syntax
  1905 redeclaration.
  1906 
  1907 * Locale declaration: 'includes' disallowed.
  1908 
  1909 * Proper static binding of attribute syntax -- i.e. types / terms /
  1910 facts mentioned as arguments are always those of the locale definition
  1911 context, independently of the context of later invocations.  Moreover,
  1912 locale operations (renaming and type / term instantiation) are applied
  1913 to attribute arguments as expected.
  1914 
  1915 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1916 actual attributes; rare situations may require Attrib.attribute to
  1917 embed those attributes into Attrib.src that lack concrete syntax.
  1918 Attribute implementations need to cooperate properly with the static
  1919 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1920 Attrib.XXX_thm etc. already do the right thing without further
  1921 intervention.  Only unusual applications -- such as "where" or "of"
  1922 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1923 on the context and the facts involved -- may have to assign parsed
  1924 values to argument tokens explicitly.
  1925 
  1926 * Changed parameter management in theorem generation for long goal
  1927 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1928 theorem statement in rare situations.
  1929 
  1930 * Locale inspection command 'print_locale' omits notes elements.  Use
  1931 'print_locale!' to have them included in the output.
  1932 
  1933 
  1934 *** Provers ***
  1935 
  1936 * Provers/hypsubst.ML: improved version of the subst method, for
  1937 single-step rewriting: it now works in bound variable contexts. New is
  1938 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1939 rewrite a different subterm than the original subst method, which is
  1940 still available as 'simplesubst'.
  1941 
  1942 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1943 and quasi orders.
  1944 
  1945 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1946 reflexive-transitive closure of relations.
  1947 
  1948 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1949 limit (previously hard-coded with a value of 20) user-definable.
  1950 
  1951 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1952 is peformed already.  Object-logics merely need to finish their
  1953 initial simpset configuration as before.  INCOMPATIBILITY.
  1954 
  1955 
  1956 *** HOL ***
  1957 
  1958 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1959 
  1960   syntax (epsilon)
  1961     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1962 
  1963 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1964 and x-symbol; use option '-m epsilon' to get it actually printed.
  1965 Moreover, the mathematically important symbolic identifier \<epsilon>
  1966 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1967 
  1968 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1969 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1970 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1971 support corresponding Isar calculations.
  1972 
  1973 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1974 instead of ":".
  1975 
  1976 * theory SetInterval: changed the syntax for open intervals:
  1977 
  1978   Old       New
  1979   {..n(}    {..<n}
  1980   {)n..}    {n<..}
  1981   {m..n(}   {m..<n}
  1982   {)m..n}   {m<..n}
  1983   {)m..n(}  {m<..<n}
  1984 
  1985 The old syntax is still supported but will disappear in the next
  1986 release.  For conversion use the following Emacs search and replace
  1987 patterns (these are not perfect but work quite well):
  1988 
  1989   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1990   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1991 
  1992 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1993 equalities in commutative rings; method 'algebra' provides a generic
  1994 interface.
  1995 
  1996 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1997 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1998 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1999 be a tuple pattern.
  2000 
  2001 Some new syntax forms are available:
  2002 
  2003   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2004   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2005   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2006   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2007 
  2008 The latter form "\<Sum>x < k. e" used to be based on a separate
  2009 function "Summation", which has been discontinued.
  2010 
  2011 * theory Finite_Set: in structured induction proofs, the insert case
  2012 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2013 (insert F x)'.
  2014 
  2015 * The 'refute' command has been extended to support a much larger
  2016 fragment of HOL, including axiomatic type classes, constdefs and
  2017 typedefs, inductive datatypes and recursion.
  2018 
  2019 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2020 Requires zChaff with proof generation to be installed.  See
  2021 HOL/ex/SAT_Examples.thy for examples.
  2022 
  2023 * Datatype induction via method 'induct' now preserves the name of the
  2024 induction variable. For example, when proving P(xs::'a list) by
  2025 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2026 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2027 in unstructured proof scripts.
  2028 
  2029 * Reworked implementation of records.  Improved scalability for
  2030 records with many fields, avoiding performance problems for type
  2031 inference. Records are no longer composed of nested field types, but
  2032 of nested extension types. Therefore the record type only grows linear
  2033 in the number of extensions and not in the number of fields.  The
  2034 top-level (users) view on records is preserved.  Potential
  2035 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2036 old record representation. The type generated for a record is called
  2037 <record_name>_ext_type.
  2038 
  2039 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2040 proofs triggered by a record definition or a simproc (if
  2041 quick_and_dirty is enabled).  Definitions of large records can take
  2042 quite long.
  2043 
  2044 New simproc record_upd_simproc for simplification of multiple record
  2045 updates enabled by default.  Moreover, trivial updates are also
  2046 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2047 occasionally, since simplification is more powerful by default.
  2048 
  2049 * typedef: proper support for polymorphic sets, which contain extra
  2050 type-variables in the term.
  2051 
  2052 * Simplifier: automatically reasons about transitivity chains
  2053 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2054 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2055 old proofs break occasionally as simplification may now solve more
  2056 goals than previously.
  2057 
  2058 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2059 present.  Works for all partial orders (class "order"), in particular
  2060 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2061 just like y <= x.
  2062 
  2063 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2064 bound variable or a constant then the let is unfolded.  Otherwise
  2065 first a is simplified to b, and then f b is simplified to g. If
  2066 possible we abstract b from g arriving at "let x = b in h x",
  2067 otherwise we unfold the let and arrive at g.  The simproc can be
  2068 enabled/disabled by the reference use_let_simproc.  Potential
  2069 INCOMPATIBILITY since simplification is more powerful by default.
  2070 
  2071 * Classical reasoning: the meson method now accepts theorems as arguments.
  2072 
  2073 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2074 jobs to provide advice on the provability of subgoals.
  2075 
  2076 * Theory OrderedGroup and Ring_and_Field: various additions and
  2077 improvements to faciliate calculations involving equalities and
  2078 inequalities.
  2079 
  2080 The following theorems have been eliminated or modified
  2081 (INCOMPATIBILITY):
  2082 
  2083   abs_eq             now named abs_of_nonneg
  2084   abs_of_ge_0        now named abs_of_nonneg
  2085   abs_minus_eq       now named abs_of_nonpos
  2086   imp_abs_id         now named abs_of_nonneg
  2087   imp_abs_neg_id     now named abs_of_nonpos
  2088   mult_pos           now named mult_pos_pos
  2089   mult_pos_le        now named mult_nonneg_nonneg
  2090   mult_pos_neg_le    now named mult_nonneg_nonpos
  2091   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2092   mult_neg           now named mult_neg_neg
  2093   mult_neg_le        now named mult_nonpos_nonpos
  2094 
  2095 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2096      
  2097      zero_le_square
  2098      not_square_less_zero 
  2099 
  2100   The following lemmas have been deleted from Real/RealPow:
  2101   
  2102      realpow_zero_zero
  2103      realpow_two
  2104      realpow_less
  2105      zero_le_power
  2106      realpow_two_le
  2107      abs_realpow_two
  2108      realpow_two_abs     
  2109 
  2110 * Theory Parity: added rules for simplifying exponents.
  2111 
  2112 * Theory List:
  2113 
  2114 The following theorems have been eliminated or modified
  2115 (INCOMPATIBILITY):
  2116 
  2117   list_all_Nil       now named list_all.simps(1)
  2118   list_all_Cons      now named list_all.simps(2)
  2119   list_all_conv      now named list_all_iff
  2120   set_mem_eq         now named mem_iff
  2121 
  2122 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2123 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2124 
  2125 
  2126 *** HOL-Complex ***
  2127 
  2128 * Theory RealDef: better support for embedding natural numbers and
  2129 integers in the reals.
  2130 
  2131 The following theorems have been eliminated or modified
  2132 (INCOMPATIBILITY):
  2133 
  2134   exp_ge_add_one_self  now requires no hypotheses
  2135   real_of_int_add      reversed direction of equality (use [symmetric])
  2136   real_of_int_minus    reversed direction of equality (use [symmetric])
  2137   real_of_int_diff     reversed direction of equality (use [symmetric])
  2138   real_of_int_mult     reversed direction of equality (use [symmetric])
  2139 
  2140 * Theory RComplete: expanded support for floor and ceiling functions.
  2141 
  2142 * Theory Ln is new, with properties of the natural logarithm
  2143 
  2144 * Hyperreal: There is a new type constructor "star" for making
  2145 nonstandard types.  The old type names are now type synonyms:
  2146 
  2147   hypreal = real star
  2148   hypnat = nat star
  2149   hcomplex = complex star
  2150 
  2151 * Hyperreal: Many groups of similarly-defined constants have been
  2152 replaced by polymorphic versions (INCOMPATIBILITY):
  2153 
  2154   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2155 
  2156   starset      <-- starsetNat, starsetC
  2157   *s*          <-- *sNat*, *sc*
  2158   starset_n    <-- starsetNat_n, starsetC_n
  2159   *sn*         <-- *sNatn*, *scn*
  2160   InternalSets <-- InternalNatSets, InternalCSets
  2161 
  2162   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2163   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2164   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2165   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2166   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2167 
  2168 * Hyperreal: Many type-specific theorems have been removed in favor of
  2169 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2170 
  2171   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2172   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2173   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2174   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2175   right_minus <-- hypreal_add_minus
  2176   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2177   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2178   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2179   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2180   mult_1_right <-- hcomplex_mult_one_right
  2181   mult_zero_left <-- hcomplex_mult_zero_left
  2182   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2183   right_distrib <-- hypnat_add_mult_distrib2
  2184   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2185   right_inverse <-- hypreal_mult_inverse
  2186   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2187   order_refl <-- {hypreal,hypnat}_le_refl
  2188   order_trans <-- {hypreal,hypnat}_le_trans
  2189   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2190   order_less_le <-- {hypreal,hypnat}_less_le
  2191   linorder_linear <-- {hypreal,hypnat}_le_linear
  2192   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2193   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2194   add_nonneg_nonneg <-- hypreal_le_add_order
  2195 
  2196 * Hyperreal: Separate theorems having to do with type-specific
  2197 versions of constants have been merged into theorems that apply to the
  2198 new polymorphic constants (INCOMPATIBILITY):
  2199 
  2200   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2201   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2202   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2203   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2204   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2205   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2206   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2207   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2208   STAR_diff <-- {STAR,STARC}_diff
  2209   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2210     STARC_hcomplex_of_complex}_image_subset
  2211   starset_n_Un <-- starset{Nat,C}_n_Un
  2212   starset_n_Int <-- starset{Nat,C}_n_Int
  2213   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2214   starset_n_diff <-- starset{Nat,C}_n_diff
  2215   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2216   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2217   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2218   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2219   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2220   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2221   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2222   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2223   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2224   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2225   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2226   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2227   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2228   starfun_diff <-- starfun{C,RC,CR}_diff
  2229   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2230   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2231   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2232   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2233   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2234   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2235   starfun_Id <-- starfunC_Id
  2236   starfun_approx <-- starfun{Nat,CR}_approx
  2237   starfun_capprox <-- starfun{C,RC}_capprox
  2238   starfun_abs <-- starfunNat_rabs
  2239   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2240   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2241   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2242   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2243   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2244   starfun_add_approx <-- starfunCR_add_approx
  2245   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2246   starfun_divide <-- starfun{C,CR,RC}_divide
  2247   starfun_n <-- starfun{Nat,C}_n
  2248   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2249   starfun_n_add <-- starfun{Nat,C}_n_add
  2250   starfun_n_add_minus <-- starfunNat_n_add_minus
  2251   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2252   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2253   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2254 
  2255   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2256   star_n_minus <-- {hypreal,hcomplex}_minus
  2257   star_n_diff <-- {hypreal,hcomplex}_diff
  2258   star_n_mult <-- {hypreal,hcomplex}_mult
  2259   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2260   star_n_le <-- {hypreal,hypnat}_le
  2261   star_n_less <-- {hypreal,hypnat}_less
  2262   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2263   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2264   star_n_abs <-- hypreal_hrabs
  2265   star_n_divide <-- hcomplex_divide
  2266 
  2267   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2268   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2269   star_of_diff <-- hypreal_of_real_diff
  2270   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2271   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2272   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2273   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2274   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2275   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2276   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2277   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2278   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2279   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2280   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2281   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2282   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2283   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2284   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2285   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2286   star_of_power <-- hypreal_of_real_power
  2287   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2288 
  2289 * Hyperreal: new method "transfer" that implements the transfer
  2290 principle of nonstandard analysis. With a subgoal that mentions
  2291 nonstandard types like "'a star", the command "apply transfer"
  2292 replaces it with an equivalent one that mentions only standard types.
  2293 To be successful, all free variables must have standard types; non-
  2294 standard variables must have explicit universal quantifiers.
  2295 
  2296 * Hyperreal: A theory of Taylor series.
  2297 
  2298 
  2299 *** HOLCF ***
  2300 
  2301 * Discontinued special version of 'constdefs' (which used to support
  2302 continuous functions) in favor of the general Pure one with full
  2303 type-inference.
  2304 
  2305 * New simplification procedure for solving continuity conditions; it
  2306 is much faster on terms with many nested lambda abstractions (cubic
  2307 instead of exponential time).
  2308 
  2309 * New syntax for domain package: selector names are now optional.
  2310 Parentheses should be omitted unless argument is lazy, for example:
  2311 
  2312   domain 'a stream = cons "'a" (lazy "'a stream")
  2313 
  2314 * New command 'fixrec' for defining recursive functions with pattern
  2315 matching; defining multiple functions with mutual recursion is also
  2316 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2317 sinr, or any data constructor defined by the domain package. The given
  2318 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2319 syntax and examples.
  2320 
  2321 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2322 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2323 but the proof obligation additionally includes an admissibility
  2324 requirement. The packages generate instances of class cpo or pcpo,
  2325 with continuity and strictness theorems for Rep and Abs.
  2326 
  2327 * HOLCF: Many theorems have been renamed according to a more standard naming
  2328 scheme (INCOMPATIBILITY):
  2329 
  2330   foo_inject:  "foo$x = foo$y ==> x = y"
  2331   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2332   foo_less:    "(foo$x << foo$y) = (x << y)"
  2333   foo_strict:  "foo$UU = UU"
  2334   foo_defined: "... ==> foo$x ~= UU"
  2335   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2336 
  2337 
  2338 *** ZF ***
  2339 
  2340 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2341 including the First Isomorphism Theorem (on quotienting by the kernel
  2342 of a homomorphism).
  2343 
  2344 * ZF/Simplifier: install second copy of type solver that actually
  2345 makes use of TC rules declared to Isar proof contexts (or locales);
  2346 the old version is still required for ML proof scripts.
  2347 
  2348 
  2349 *** Cube ***
  2350 
  2351 * Converted to Isar theory format; use locales instead of axiomatic
  2352 theories.
  2353 
  2354 
  2355 *** ML ***
  2356 
  2357 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2358 for ||>, ||>>, |>>,
  2359 
  2360 * Pure/library.ML no longer defines its own option datatype, but uses
  2361 that of the SML basis, which has constructors NONE and SOME instead of
  2362 None and Some, as well as exception Option.Option instead of OPTION.
  2363 The functions the, if_none, is_some, is_none have been adapted
  2364 accordingly, while Option.map replaces apsome.
  2365 
  2366 * Pure/library.ML: the exception LIST has been given up in favour of
  2367 the standard exceptions Empty and Subscript, as well as
  2368 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2369 superceded by the standard hd and tl functions etc.
  2370 
  2371 A number of basic list functions are no longer exported to the ML
  2372 toplevel, as they are variants of predefined functions.  The following
  2373 suggests how one can translate existing code:
  2374 
  2375     rev_append xs ys = List.revAppend (xs, ys)
  2376     nth_elem (i, xs) = List.nth (xs, i)
  2377     last_elem xs = List.last xs
  2378     flat xss = List.concat xss
  2379     seq fs = List.app fs
  2380     partition P xs = List.partition P xs
  2381     mapfilter f xs = List.mapPartial f xs
  2382 
  2383 * Pure/library.ML: several combinators for linear functional
  2384 transformations, notably reverse application and composition:
  2385 
  2386   x |> f                f #> g
  2387   (x, y) |-> f          f #-> g
  2388 
  2389 * Pure/library.ML: introduced/changed precedence of infix operators:
  2390 
  2391   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2392   infix 2 ?;
  2393   infix 3 o oo ooo oooo;
  2394   infix 4 ~~ upto downto;
  2395 
  2396 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2397 infix operators.
  2398 
  2399 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2400 fold_map support linear functional transformations and nesting.  For
  2401 example:
  2402 
  2403   fold f [x1, ..., xN] y =
  2404     y |> f x1 |> ... |> f xN
  2405 
  2406   (fold o fold) f [xs1, ..., xsN] y =
  2407     y |> fold f xs1 |> ... |> fold f xsN
  2408 
  2409   fold f [x1, ..., xN] =
  2410     f x1 #> ... #> f xN
  2411 
  2412   (fold o fold) f [xs1, ..., xsN] =
  2413     fold f xs1 #> ... #> fold f xsN
  2414 
  2415 * Pure/library.ML: the following selectors on type 'a option are
  2416 available:
  2417 
  2418   the:               'a option -> 'a  (*partial*)
  2419   these:             'a option -> 'a  where 'a = 'b list
  2420   the_default: 'a -> 'a option -> 'a
  2421   the_list:          'a option -> 'a list
  2422 
  2423 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2424 basic operations for association lists, following natural argument
  2425 order; moreover the explicit equality predicate passed here avoids
  2426 potentially expensive polymorphic runtime equality checks.
  2427 The old functions may be expressed as follows:
  2428 
  2429   assoc = uncurry (AList.lookup (op =))
  2430   assocs = these oo AList.lookup (op =)
  2431   overwrite = uncurry (AList.update (op =)) o swap
  2432 
  2433 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2434 
  2435   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2436   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2437 
  2438 replacing make_keylist and keyfilter (occassionally used)
  2439 Naive rewrites:
  2440 
  2441   make_keylist = AList.make
  2442   keyfilter = AList.find (op =)
  2443 
  2444 * eq_fst and eq_snd now take explicit equality parameter, thus
  2445   avoiding eqtypes. Naive rewrites:
  2446 
  2447     eq_fst = eq_fst (op =)
  2448     eq_snd = eq_snd (op =)
  2449 
  2450 * Removed deprecated apl and apr (rarely used).
  2451   Naive rewrites:
  2452 
  2453     apl (n, op) =>>= curry op n
  2454     apr (op, m) =>>= fn n => op (n, m)
  2455 
  2456 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2457 provides a reasonably efficient light-weight implementation of sets as
  2458 lists.
  2459 
  2460 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2461 few new operations; existing lookup and update are now curried to
  2462 follow natural argument order (for use with fold etc.);
  2463 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2464 
  2465 * Pure/General: output via the Isabelle channels of
  2466 writeln/warning/error etc. is now passed through Output.output, with a
  2467 hook for arbitrary transformations depending on the print_mode
  2468 (cf. Output.add_mode -- the first active mode that provides a output
  2469 function wins).  Already formatted output may be embedded into further
  2470 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2471 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2472 accommodate easy composition of diagnostic messages etc.  Programmers
  2473 rarely need to care about Output.output or Output.raw at all, with
  2474 some notable exceptions: Output.output is required when bypassing the
  2475 standard channels (writeln etc.), or in token translations to produce
  2476 properly formatted results; Output.raw is required when capturing
  2477 already output material that will eventually be presented to the user
  2478 a second time.  For the default print mode, both Output.output and
  2479 Output.raw have no effect.
  2480 
  2481 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2482 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2483 cumulative results are displayed at the end of a batch session.
  2484 
  2485 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2486 replaced by File.platform_path and File.shell_path (with appropriate
  2487 hooks).  This provides a clean interface for unusual systems where the
  2488 internal and external process view of file names are different.
  2489 
  2490 * Pure: more efficient orders for basic syntactic entities: added
  2491 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2492 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2493 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2494 orders now -- potential INCOMPATIBILITY for code that depends on a
  2495 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2496 Library.sort_strings on result).
  2497 
  2498 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2499 fold_types traverse types/terms from left to right, observing natural
  2500 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2501 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2502 
  2503 * Pure: name spaces have been refined, with significant changes of the
  2504 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2505 to extern(_table).  The plain name entry path is superceded by a
  2506 general 'naming' context, which also includes the 'policy' to produce
  2507 a fully qualified name and external accesses of a fully qualified
  2508 name; NameSpace.extend is superceded by context dependent
  2509 Sign.declare_name.  Several theory and proof context operations modify
  2510 the naming context.  Especially note Theory.restore_naming and
  2511 ProofContext.restore_naming to get back to a sane state; note that
  2512 Theory.add_path is no longer sufficient to recover from
  2513 Theory.absolute_path in particular.
  2514 
  2515 * Pure: new flags short_names (default false) and unique_names
  2516 (default true) for controlling output of qualified names.  If
  2517 short_names is set, names are printed unqualified.  If unique_names is
  2518 reset, the name prefix is reduced to the minimum required to achieve
  2519 the original result when interning again, even if there is an overlap
  2520 with earlier declarations.
  2521 
  2522 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2523 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2524 (useful for printing error messages).  INCOMPATIBILITY.
  2525 
  2526 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2527 Theory.theory are now identified, referring to the universal
  2528 Context.theory (see Pure/context.ML).  Actual signature and theory
  2529 content is managed as theory data.  The old code and interfaces were
  2530 spread over many files and structures; the new arrangement introduces
  2531 considerable INCOMPATIBILITY to gain more clarity:
  2532 
  2533   Context -- theory management operations (name, identity, inclusion,
  2534     parents, ancestors, merge, etc.), plus generic theory data;
  2535 
  2536   Sign -- logical signature and syntax operations (declaring consts,
  2537     types, etc.), plus certify/read for common entities;
  2538 
  2539   Theory -- logical theory operations (stating axioms, definitions,
  2540     oracles), plus a copy of logical signature operations (consts,
  2541     types, etc.); also a few basic management operations (Theory.copy,
  2542     Theory.merge, etc.)
  2543 
  2544 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2545 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2546 for convenience -- they merely return the theory.
  2547 
  2548 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2549 
  2550 * Pure: the Isar proof context type is already defined early in Pure
  2551 as Context.proof (note that ProofContext.context and Proof.context are
  2552 aliases, where the latter is the preferred name).  This enables other
  2553 Isabelle components to refer to that type even before Isar is present.
  2554 
  2555 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2556 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2557 any of these kinds.  For example, Sign.intern typeK is now
  2558 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2559 Theory.hide_types.  Also note that former
  2560 Theory.hide_classes/types/consts are now
  2561 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2562 internalize their arguments!  INCOMPATIBILITY.
  2563 
  2564 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2565 datatype thmref (with constructors Name and NameSelection) instead of
  2566 plain string -- INCOMPATIBILITY;
  2567 
  2568 * Pure: cases produced by proof methods specify options, where NONE
  2569 means to remove case bindings -- INCOMPATIBILITY in
  2570 (RAW_)METHOD_CASES.
  2571 
  2572 * Pure: the following operations retrieve axioms or theorems from a
  2573 theory node or theory hierarchy, respectively:
  2574 
  2575   Theory.axioms_of: theory -> (string * term) list
  2576   Theory.all_axioms_of: theory -> (string * term) list
  2577   PureThy.thms_of: theory -> (string * thm) list
  2578   PureThy.all_thms_of: theory -> (string * thm) list
  2579 
  2580 * Pure: print_tac now outputs the goal through the trace channel.
  2581 
  2582 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2583 Reference Toplevel.debug (default false) controls detailed printing
  2584 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2585 controls execution profiling -- set to 1 for time and 2 for space
  2586 (both increase the runtime).
  2587 
  2588 * Isar session: The initial use of ROOT.ML is now always timed,
  2589 i.e. the log will show the actual process times, in contrast to the
  2590 elapsed wall-clock time that the outer shell wrapper produces.
  2591 
  2592 * Simplifier: improved handling of bound variables (nameless
  2593 representation, avoid allocating new strings).  Simprocs that invoke
  2594 the Simplifier recursively should use Simplifier.inherit_bounds to
  2595 avoid local name clashes.  Failure to do so produces warnings
  2596 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2597 for further details.
  2598 
  2599 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2600 bindings for all theorems stored within a given theory; this may help
  2601 in porting non-Isar theories to Isar ones, while keeping ML proof
  2602 scripts for the time being.
  2603 
  2604 * ML operator HTML.with_charset specifies the charset begin used for
  2605 generated HTML files.  For example:
  2606 
  2607   HTML.with_charset "utf-8" use_thy "Hebrew";
  2608   HTML.with_charset "utf-8" use_thy "Chinese";
  2609 
  2610 
  2611 *** System ***
  2612 
  2613 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2614 isabelle, isatool etc.).
  2615 
  2616 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2617 isatool doc, isatool mkdir, display_drafts etc.).
  2618 
  2619 * isatool usedir: option -f allows specification of the ML file to be
  2620 used by Isabelle; default is ROOT.ML.
  2621 
  2622 * New isatool version outputs the version identifier of the Isabelle
  2623 distribution being used.
  2624 
  2625 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2626 (containing Boolean satisfiability problems) into Isabelle/HOL
  2627 theories.
  2628 
  2629 
  2630 
  2631 New in Isabelle2004 (April 2004)
  2632 --------------------------------
  2633 
  2634 *** General ***
  2635 
  2636 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2637   Replaces linorder.ML.
  2638 
  2639 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2640   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2641   (\<a>...\<z>), are now considered normal letters, and can therefore
  2642   be used anywhere where an ASCII letter (a...zA...Z) has until
  2643   now. COMPATIBILITY: This obviously changes the parsing of some
  2644   terms, especially where a symbol has been used as a binder, say
  2645   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2646   as an identifier.  Fix it by inserting a space around former
  2647   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2648   existing theory and ML files.
  2649 
  2650 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2651 
  2652 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2653   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2654   a normal (but invisible) letter. For multiple letter subscripts repeat
  2655   \<^isub> like this: x\<^isub>1\<^isub>2.
  2656 
  2657 * Pure: There are now sub-/superscripts that can span more than one
  2658   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2659   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2660   superscript. The new control characters are not identifier parts.
  2661 
  2662 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2663   content of "..." to the latex file instead of \isacntrl... . The "..."
  2664   may consist of any printable characters excluding the end bracket >.
  2665 
  2666 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2667   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2668   declare constants "final", which prevents their being given a definition
  2669   later.  It is useful for constants whose behaviour is fixed axiomatically
  2670   rather than definitionally, such as the meta-logic connectives.
  2671 
  2672 * Pure: 'instance' now handles general arities with general sorts
  2673   (i.e. intersections of classes),
  2674 
  2675 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2676   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2677   It can be changed to alter the colors/layout of generated pages.
  2678 
  2679 
  2680 *** Isar ***
  2681 
  2682 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2683   cut_tac, subgoal_tac and thin_tac:
  2684   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2685     locales are no longer forced to write Isar proof scripts.
  2686     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2687     emulations.
  2688   - INCOMPATIBILITY: names of variables to be instantiated may no
  2689     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2690     This is consistent with the instantiation attribute "where".
  2691 
  2692 * Attributes "where" and "of":
  2693   - Now take type variables of instantiated theorem into account when reading
  2694     the instantiation string.  This fixes a bug that caused instantiated
  2695     theorems to have too special types in some circumstances.
  2696   - "where" permits explicit instantiations of type variables.
  2697 
  2698 * Calculation commands "moreover" and "also" no longer interfere with
  2699   current facts ("this"), admitting arbitrary combinations with "then"
  2700   and derived forms.
  2701 
  2702 * Locales:
  2703   - Goal statements involving the context element "includes" no longer
  2704     generate theorems with internal delta predicates (those ending on
  2705     "_axioms") in the premise.
  2706     Resolve particular premise with <locale>.intro to obtain old form.
  2707   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2708     specification and "includes" elements in goal statement.
  2709   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2710     [intro?] and [elim?] (respectively) by default.
  2711   - Experimental command for instantiation of locales in proof contexts:
  2712         instantiate <label>[<attrs>]: <loc>
  2713     Instantiates locale <loc> and adds all its theorems to the current context
  2714     taking into account their attributes.  Label and attrs are optional
  2715     modifiers, like in theorem declarations.  If present, names of
  2716     instantiated theorems are qualified with <label>, and the attributes
  2717     <attrs> are applied after any attributes these theorems might have already.
  2718       If the locale has assumptions, a chained fact of the form
  2719     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2720     are derived.  The command does not support old-style locales declared
  2721     with "locale (open)".
  2722       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2723 
  2724 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2725   (Isar) contexts.
  2726 
  2727 
  2728 *** HOL ***
  2729 
  2730 * Proof import: new image HOL4 contains the imported library from
  2731   the HOL4 system with about 2500 theorems. It is imported by
  2732   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2733   can be used like any other Isabelle image.  See
  2734   HOL/Import/HOL/README for more information.
  2735 
  2736 * Simplifier:
  2737   - Much improved handling of linear and partial orders.
  2738     Reasoners for linear and partial orders are set up for type classes
  2739     "linorder" and "order" respectively, and are added to the default simpset
  2740     as solvers.  This means that the simplifier can build transitivity chains
  2741     to solve goals from the assumptions.
  2742   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2743     of blast or auto after simplification become unnecessary because the goal
  2744     is solved by simplification already.
  2745 
  2746 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2747     all proved in axiomatic type classes for semirings, rings and fields.
  2748 
  2749 * Numerics:
  2750   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2751     now formalized using the Ring_and_Field theory mentioned above.
  2752   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2753     than before, because now they are set up once in a generic manner.
  2754   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2755     Look for the general versions in Ring_and_Field (and Power if they concern
  2756     exponentiation).
  2757 
  2758 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2759 
  2760 * Records:
  2761   - Record types are now by default printed with their type abbreviation
  2762     instead of the list of all field types. This can be configured via
  2763     the reference "print_record_type_abbr".
  2764   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2765     (not enabled by default).
  2766   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2767     EX x. x = sel r to True (not enabled by default).
  2768   - Tactic "record_split_simp_tac" to split and simplify records added.
  2769 
  2770 * 'specification' command added, allowing for definition by
  2771   specification.  There is also an 'ax_specification' command that
  2772   introduces the new constants axiomatically.
  2773 
  2774 * arith(_tac) is now able to generate counterexamples for reals as well.
  2775 
  2776 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2777 
  2778 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2779   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2780 
  2781 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2782   matrix theory to linear programming.
  2783 
  2784 * Unions and Intersections:
  2785   The latex output syntax of UN and INT has been changed
  2786   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2787   i.e. the index formulae has become a subscript.
  2788   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2789 
  2790 * Unions and Intersections over Intervals:
  2791   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2792   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2793   like in normal math, and corresponding versions for < and for intersection.
  2794 
  2795 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2796   lexicographic dictonary ordering has been added as "lexord".
  2797 
  2798 * ML: the legacy theory structures Int and List have been removed. They had
  2799   conflicted with ML Basis Library structures having the same names.
  2800 
  2801 * 'refute' command added to search for (finite) countermodels.  Only works
  2802   for a fragment of HOL.  The installation of an external SAT solver is
  2803   highly recommended.  See "HOL/Refute.thy" for details.
  2804 
  2805 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2806   formulae under an assignment of free variables to random values.
  2807   In contrast to 'refute', it can deal with inductive datatypes,
  2808   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2809   for examples.
  2810 
  2811 
  2812 *** HOLCF ***
  2813 
  2814 * Streams now come with concatenation and are part of the HOLCF image
  2815 
  2816 
  2817 
  2818 New in Isabelle2003 (May 2003)
  2819 ------------------------------
  2820 
  2821 *** General ***
  2822 
  2823 * Provers/simplifier:
  2824 
  2825   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2826     Assumptions are now subject to complete mutual simplification,
  2827     not just from left to right. The simplifier now preserves
  2828     the order of assumptions.
  2829 
  2830     Potential INCOMPATIBILITY:
  2831 
  2832     -- simp sometimes diverges where the old version did
  2833        not, e.g. invoking simp on the goal
  2834 
  2835         [| P (f x); y = x; f x = f y |] ==> Q
  2836 
  2837        now gives rise to the infinite reduction sequence
  2838 
  2839         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2840 
  2841        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2842        kind of problem.
  2843 
  2844     -- Tactics combining classical reasoner and simplification (such as auto)
  2845        are also affected by this change, because many of them rely on
  2846        simp. They may sometimes diverge as well or yield a different numbers
  2847        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2848        in case of problems. Sometimes subsequent calls to the classical
  2849        reasoner will fail because a preceeding call to the simplifier too
  2850        eagerly simplified the goal, e.g. deleted redundant premises.
  2851 
  2852   - The simplifier trace now shows the names of the applied rewrite rules
  2853 
  2854   - You can limit the number of recursive invocations of the simplifier
  2855     during conditional rewriting (where the simplifie tries to solve the
  2856     conditions before applying the rewrite rule):
  2857     ML "simp_depth_limit := n"
  2858     where n is an integer. Thus you can force termination where previously
  2859     the simplifier would diverge.
  2860 
  2861   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2862 
  2863   - No longer aborts on failed congruence proof.  Instead, the
  2864     congruence is ignored.
  2865 
  2866 * Pure: New generic framework for extracting programs from constructive
  2867   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2868   as HOL/Extraction for some case studies.
  2869 
  2870 * Pure: The main goal of the proof state is no longer shown by default, only
  2871 the subgoals. This behaviour is controlled by a new flag.
  2872    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2873 (ML: Proof.show_main_goal).
  2874 
  2875 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2876 rules whose conclusion matches subgoal 1:
  2877       PG menu: Isabelle/Isar -> Show me -> matching rules
  2878 The rules are ordered by how closely they match the subgoal.
  2879 In particular, rules that solve a subgoal outright are displayed first
  2880 (or rather last, the way they are printed).
  2881 (ML: ProofGeneral.print_intros())
  2882 
  2883 * Pure: New flag trace_unify_fail causes unification to print
  2884 diagnostic information (PG: in trace buffer) when it fails. This is
  2885 useful for figuring out why single step proofs like rule, erule or
  2886 assumption failed.
  2887 
  2888 * Pure: Locale specifications now produce predicate definitions
  2889 according to the body of text (covering assumptions modulo local
  2890 definitions); predicate "loc_axioms" covers newly introduced text,
  2891 while "loc" is cumulative wrt. all included locale expressions; the
  2892 latter view is presented only on export into the global theory
  2893 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2894 on the old view without predicates;
  2895 
  2896 * Pure: predefined locales "var" and "struct" are useful for sharing
  2897 parameters (as in CASL, for example); just specify something like
  2898 ``var x + var y + struct M'' as import;
  2899 
  2900 * Pure: improved thms_containing: proper indexing of facts instead of
  2901 raw theorems; check validity of results wrt. current name space;
  2902 include local facts of proof configuration (also covers active
  2903 locales), cover fixed variables in index; may use "_" in term
  2904 specification; an optional limit for the number of printed facts may
  2905 be given (the default is 40);
  2906 
  2907 * Pure: disallow duplicate fact bindings within new-style theory files
  2908 (batch-mode only);
  2909 
  2910 * Provers: improved induct method: assumptions introduced by case
  2911 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2912 the goal statement); "foo" still refers to all facts collectively;
  2913 
  2914 * Provers: the function blast.overloaded has been removed: all constants
  2915 are regarded as potentially overloaded, which improves robustness in exchange
  2916 for slight decrease in efficiency;
  2917 
  2918 * Provers/linorder: New generic prover for transitivity reasoning over
  2919 linear orders.  Note: this prover is not efficient!
  2920 
  2921 * Isar: preview of problems to finish 'show' now produce an error
  2922 rather than just a warning (in interactive mode);
  2923 
  2924 
  2925 *** HOL ***
  2926 
  2927 * arith(_tac)
  2928 
  2929  - Produces a counter example if it cannot prove a goal.
  2930    Note that the counter example may be spurious if the goal is not a formula
  2931    of quantifier-free linear arithmetic.
  2932    In ProofGeneral the counter example appears in the trace buffer.
  2933 
  2934  - Knows about div k and mod k where k is a numeral of type nat or int.
  2935 
  2936  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2937    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2938    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2939 
  2940 * simp's arithmetic capabilities have been enhanced a bit: it now
  2941 takes ~= in premises into account (by performing a case split);
  2942 
  2943 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2944 are distributed over a sum of terms;
  2945 
  2946 * New tactic "trans_tac" and method "trans" instantiate
  2947 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2948 "<=", "<" and "=").
  2949 
  2950 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2951 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2952 
  2953 * 'typedef' command has new option "open" to suppress the set
  2954 definition;
  2955 
  2956 * functions Min and Max on finite sets have been introduced (theory
  2957 Finite_Set);
  2958 
  2959 * attribute [symmetric] now works for relations as well; it turns
  2960 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2961 
  2962 * induct over a !!-quantified statement (say !!x1..xn):
  2963   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2964 
  2965 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2966 %x. None. Warning: empty_def now refers to the previously hidden definition
  2967 of the empty set.
  2968 
  2969 * Algebra: formalization of classical algebra.  Intended as base for
  2970 any algebraic development in Isabelle.  Currently covers group theory
  2971 (up to Sylow's theorem) and ring theory (Universal Property of
  2972 Univariate Polynomials).  Contributions welcome;
  2973 
  2974 * GroupTheory: deleted, since its material has been moved to Algebra;
  2975 
  2976 * Complex: new directory of the complex numbers with numeric constants,
  2977 nonstandard complex numbers, and some complex analysis, standard and
  2978 nonstandard (Jacques Fleuriot);
  2979 
  2980 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2981 
  2982 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2983 Fleuriot);
  2984 
  2985 * Real/HahnBanach: updated and adapted to locales;
  2986 
  2987 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2988 Gray and Kramer);
  2989 
  2990 * UNITY: added the Meier-Sanders theory of progress sets;
  2991 
  2992 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2993 as abstract algorithms, instantiated to the JVM;
  2994 
  2995 * Bali: Java source language formalization. Type system, operational
  2996 semantics, axiomatic semantics. Supported language features:
  2997 classes, interfaces, objects,virtual methods, static methods,
  2998 static/instance fields, arrays, access modifiers, definite
  2999 assignment, exceptions.
  3000 
  3001 
  3002 *** ZF ***
  3003 
  3004 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3005 universe, etc.);
  3006 
  3007 * Main ZF: virtually all theories converted to new-style format;
  3008 
  3009 
  3010 *** ML ***
  3011 
  3012 * Pure: Tactic.prove provides sane interface for internal proofs;
  3013 omits the infamous "standard" operation, so this is more appropriate
  3014 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3015 
  3016 * Pure: improved error reporting of simprocs;
  3017 
  3018 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3019 up simprocs;
  3020 
  3021 
  3022 *** Document preparation ***
  3023 
  3024 * uses \par instead of \\ for line breaks in theory text. This may
  3025 shift some page breaks in large documents. To get the old behaviour
  3026 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3027 
  3028 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3029 other packages
  3030 
  3031 * \<euro> now needs package babel/greek instead of marvosym (which
  3032 broke \Rightarrow)
  3033 
  3034 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3035 textcomp package)
  3036 
  3037 
  3038 
  3039 New in Isabelle2002 (March 2002)
  3040 --------------------------------
  3041 
  3042 *** Document preparation ***
  3043 
  3044 * greatly simplified document preparation setup, including more
  3045 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3046 instructive isatool mkdir; users should basically be able to get
  3047 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3048 users may run a separate document processing stage manually like this:
  3049 "isatool usedir -D output HOL Test && isatool document Test/output";
  3050 
  3051 * theory dependency graph may now be incorporated into documents;
  3052 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3053 with \includegraphics of LaTeX;
  3054 
  3055 * proper spacing of consecutive markup elements, especially text
  3056 blocks after section headings;
  3057 
  3058 * support bold style (for single symbols only), input syntax is like
  3059 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3060 
  3061 * \<bullet> is now output as bold \cdot by default, which looks much
  3062 better in printed text;
  3063 
  3064 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3065 note that these symbols are currently unavailable in Proof General /
  3066 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3067 
  3068 * isatool latex no longer depends on changed TEXINPUTS, instead
  3069 isatool document copies the Isabelle style files to the target
  3070 location;
  3071 
  3072 
  3073 *** Isar ***
  3074 
  3075 * Pure/Provers: improved proof by cases and induction;
  3076   - 'case' command admits impromptu naming of parameters (such as
  3077     "case (Suc n)");
  3078   - 'induct' method divinates rule instantiation from the inductive
  3079     claim; no longer requires excessive ?P bindings for proper
  3080     instantiation of cases;
  3081   - 'induct' method properly enumerates all possibilities of set/type
  3082     rules; as a consequence facts may be also passed through *type*
  3083     rules without further ado;
  3084   - 'induct' method now derives symbolic cases from the *rulified*
  3085     rule (before it used to rulify cases stemming from the internal
  3086     atomized version); this means that the context of a non-atomic
  3087     statement becomes is included in the hypothesis, avoiding the
  3088     slightly cumbersome show "PROP ?case" form;
  3089   - 'induct' may now use elim-style induction rules without chaining
  3090     facts, using ``missing'' premises from the goal state; this allows
  3091     rules stemming from inductive sets to be applied in unstructured
  3092     scripts, while still benefitting from proper handling of non-atomic
  3093     statements; NB: major inductive premises need to be put first, all
  3094     the rest of the goal is passed through the induction;
  3095   - 'induct' proper support for mutual induction involving non-atomic
  3096     rule statements (uses the new concept of simultaneous goals, see
  3097     below);
  3098   - append all possible rule selections, but only use the first
  3099     success (no backtracking);
  3100   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3101   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3102   - added 'print_induct_rules' (covered by help item in recent Proof
  3103     General versions);
  3104   - moved induct/cases attributes to Pure, methods to Provers;
  3105   - generic method setup instantiated for FOL and HOL;
  3106 
  3107 * Pure: support multiple simultaneous goal statements, for example
  3108 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3109 meta-level mechanism, this acts as if several individual goals had
  3110 been stated separately; in particular common proof methods need to be
  3111 repeated in order to cover all claims; note that a single elimination
  3112 step is *not* sufficient to establish the two conjunctions, so this
  3113 fails:
  3114 
  3115   assume "A & B" then have A and B ..   (*".." fails*)
  3116 
  3117 better use "obtain" in situations as above; alternative refer to
  3118 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3119 
  3120 * Pure: proper integration with ``locales''; unlike the original
  3121 version by Florian Kammller, Isar locales package high-level proof
  3122 contexts rather than raw logical ones (e.g. we admit to include
  3123 attributes everywhere); operations on locales include merge and
  3124 rename; support for implicit arguments (``structures''); simultaneous
  3125 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3126 some examples;
  3127 
  3128 * Pure: the following commands have been ``localized'', supporting a
  3129 target locale specification "(in name)": 'lemma', 'theorem',
  3130 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3131 stored both within the locale and at the theory level (exported and
  3132 qualified by the locale name);
  3133 
  3134 * Pure: theory goals may now be specified in ``long'' form, with
  3135 ad-hoc contexts consisting of arbitrary locale elements. for example
  3136 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3137 definitions may be given, too); the result is a meta-level rule with
  3138 the context elements being discharged in the obvious way;
  3139 
  3140 * Pure: new proof command 'using' allows to augment currently used
  3141 facts after a goal statement ('using' is syntactically analogous to
  3142 'apply', but acts on the goal's facts only); this allows chained facts
  3143 to be separated into parts given before and after a claim, as in
  3144 ``from a and b have C using d and e <proof>'';
  3145 
  3146 * Pure: renamed "antecedent" case to "rule_context";
  3147 
  3148 * Pure: new 'judgment' command records explicit information about the
  3149 object-logic embedding (used by several tools internally); no longer
  3150 use hard-wired "Trueprop";
  3151 
  3152 * Pure: added 'corollary' command;
  3153 
  3154 * Pure: fixed 'token_translation' command;
  3155 
  3156 * Pure: removed obsolete 'exported' attribute;
  3157 
  3158 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3159 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3160 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3161 
  3162 * Pure: method 'atomize' presents local goal premises as object-level
  3163 statements (atomic meta-level propositions); setup controlled via
  3164 rewrite rules declarations of 'atomize' attribute; example
  3165 application: 'induct' method with proper rule statements in improper
  3166 proof *scripts*;
  3167 
  3168 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3169 now consider the syntactic context of assumptions, giving a better
  3170 chance to get type-inference of the arguments right (this is
  3171 especially important for locales);
  3172 
  3173 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3174 mode;
  3175 
  3176 * Pure/obtain: the formal conclusion "thesis", being marked as
  3177 ``internal'', may no longer be reference directly in the text;
  3178 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3179 situations;
  3180 
  3181 * Pure: generic 'sym' attribute which declares a rule both as pure
  3182 'elim?' and for the 'symmetric' operation;
  3183 
  3184 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3185 text; the fixed correlation with particular command syntax has been
  3186 discontinued;
  3187 
  3188 * Pure: new method 'rules' is particularly well-suited for proof
  3189 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3190 but often produces more compact proof terms with less detours;
  3191 
  3192 * Pure/Provers/classical: simplified integration with pure rule
  3193 attributes and methods; the classical "intro?/elim?/dest?"
  3194 declarations coincide with the pure ones; the "rule" method no longer
  3195 includes classically swapped intros; "intro" and "elim" methods no
  3196 longer pick rules from the context; also got rid of ML declarations
  3197 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3198 INCOMPATIBILITY;
  3199 
  3200 * Provers/classical: attribute 'swapped' produces classical inversions
  3201 of introduction rules;
  3202 
  3203 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3204 rules instead of full simplifier context; 'iff' attribute handles
  3205 conditional rules;
  3206 
  3207 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3208 
  3209 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3210 "(permissive)" option to recover old behavior;
  3211 
  3212 * HOL: 'inductive' no longer features separate (collective) attributes
  3213 for 'intros' (was found too confusing);
  3214 
  3215 * HOL: properly declared induction rules less_induct and
  3216 wf_induct_rule;
  3217 
  3218 
  3219 *** HOL ***
  3220 
  3221 * HOL: moved over to sane numeral syntax; the new policy is as
  3222 follows:
  3223 
  3224   - 0 and 1 are polymorphic constants, which are defined on any
  3225   numeric type (nat, int, real etc.);
  3226 
  3227   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3228   binary representation internally;
  3229 
  3230   - type nat has special constructor Suc, and generally prefers Suc 0
  3231   over 1::nat and Suc (Suc 0) over 2::nat;
  3232 
  3233 This change may cause significant problems of INCOMPATIBILITY; here
  3234 are some hints on converting existing sources:
  3235 
  3236   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3237   entities, so expressions involving "-" (unary or binary minus) need
  3238   to be spaced properly;
  3239 
  3240   - existing occurrences of "1" may need to be constraint "1::nat" or
  3241   even replaced by Suc 0; similar for old "2";
  3242 
  3243   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3244 
  3245   - remove all special provisions on numerals in proofs;
  3246 
  3247 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3248 representation (depends on bin_arith_simps in the default context);
  3249 
  3250 * HOL: symbolic syntax for x^2 (numeral 2);
  3251 
  3252 * HOL: the class of all HOL types is now called "type" rather than
  3253 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3254 in axclass/classes, instance/arities, and (usually rare) occurrences
  3255 in typings (of consts etc.); internally the class is called
  3256 "HOL.type", ML programs should refer to HOLogic.typeS;
  3257 
  3258 * HOL/record package improvements:
  3259   - new derived operations "fields" to build a partial record section,
  3260     "extend" to promote a fixed record to a record scheme, and
  3261     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3262     declared as simp by default;
  3263   - shared operations ("more", "fields", etc.) now need to be always
  3264     qualified) --- potential INCOMPATIBILITY;
  3265   - removed "make_scheme" operations (use "make" with "extend") --
  3266     INCOMPATIBILITY;
  3267   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3268   - provides cases/induct rules for use with corresponding Isar
  3269     methods (for concrete records, record schemes, concrete more
  3270     parts, and schematic more parts -- in that order);
  3271   - internal definitions directly based on a light-weight abstract
  3272     theory of product types over typedef rather than datatype;
  3273 
  3274 * HOL: generic code generator for generating executable ML code from
  3275 specifications; specific support for HOL constructs such as inductive
  3276 datatypes and sets, as well as recursive functions; can be invoked
  3277 via 'generate_code' theory section;
  3278 
  3279 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3280 
  3281 * HOL: consolidated and renamed several theories.  In particular:
  3282         Ord.thy has been absorbed into HOL.thy
  3283         String.thy has been absorbed into List.thy
  3284 
  3285 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3286 (beware of argument permutation!);
  3287 
  3288 * HOL: linorder_less_split superseded by linorder_cases;
  3289 
  3290 * HOL/List: "nodups" renamed to "distinct";
  3291 
  3292 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3293 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3294   - Ex_def has changed, now need to use some_eq_ex
  3295 
  3296 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3297 in this (rare) case use:
  3298 
  3299   delSWrapper "split_all_tac"
  3300   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3301 
  3302 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3303 MAY FAIL;
  3304 
  3305 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3306 Isabelle's type classes, ^ on functions and relations has too general
  3307 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3308 necessary to attach explicit type constraints;
  3309 
  3310 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3311 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3312 renamed accordingly (eg "compI" -> "rel_compI").
  3313 
  3314 * HOL: syntax translations now work properly with numerals and records
  3315 expressions;
  3316 
  3317 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3318 of "lam" -- INCOMPATIBILITY;
  3319 
  3320 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3321 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3322 renamed "Product_Type.unit";
  3323 
  3324 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3325 
  3326 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3327 the "cases" method);
  3328 
  3329 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3330 Florian Kammller);
  3331 
  3332 * HOL/IMP: updated and converted to new-style theory format; several
  3333 parts turned into readable document, with proper Isar proof texts and
  3334 some explanations (by Gerwin Klein);
  3335 
  3336 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3337 
  3338 * HOL-Hyperreal is now a logic image;
  3339 
  3340 
  3341 *** HOLCF ***
  3342 
  3343 * Isar: consts/constdefs supports mixfix syntax for continuous
  3344 operations;
  3345 
  3346 * Isar: domain package adapted to new-style theory format, e.g. see
  3347 HOLCF/ex/Dnat.thy;
  3348 
  3349 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3350 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3351 lift.induct_tac, always use UU instead of Undef;
  3352 
  3353 * HOLCF/IMP: updated and converted to new-style theory;
  3354 
  3355 
  3356 *** ZF ***
  3357 
  3358 * Isar: proper integration of logic-specific tools and packages,
  3359 including theory commands '(co)inductive', '(co)datatype',
  3360 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3361 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3362 
  3363 * theory Main no longer includes AC; for the Axiom of Choice, base
  3364 your theory on Main_ZFC;
  3365 
  3366 * the integer library now covers quotients and remainders, with many
  3367 laws relating division to addition, multiplication, etc.;
  3368 
  3369 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3370 typeless version of the formalism;
  3371 
  3372 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3373 format;
  3374 
  3375 * ZF/Induct: new directory for examples of inductive definitions,
  3376 including theory Multiset for multiset orderings; converted to
  3377 new-style theory format;
  3378 
  3379 * ZF: many new theorems about lists, ordinals, etc.;
  3380 
  3381 
  3382 *** General ***
  3383 
  3384 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3385 variable proof controls level of detail: 0 = no proofs (only oracle
  3386 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3387 also ref manual for further ML interfaces;
  3388 
  3389 * Pure/axclass: removed obsolete ML interface
  3390 goal_subclass/goal_arity;
  3391 
  3392 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3393 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3394 separate tokens, so expressions involving minus need to be spaced
  3395 properly;
  3396 
  3397 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3398 rather than "infixl" or "infixr";
  3399 
  3400 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3401 sort constraint specifications in type inference; e.g. "x::_::foo"
  3402 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3403 type variable);
  3404 
  3405 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3406 control output of nested => (types); the default behavior is
  3407 "type_brackets";
  3408 
  3409 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3410 tokens into AST constants;
  3411 
  3412 * Pure/syntax: prefer later declarations of translations and print
  3413 translation functions; potential INCOMPATIBILITY: need to reverse
  3414 multiple declarations for same syntax element constant;
  3415 
  3416 * Pure/show_hyps reset by default (in accordance to existing Isar
  3417 practice);
  3418 
  3419 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3420 addSafter;
  3421 
  3422 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3423 as well;
  3424 
  3425 * system: tested support for MacOS X; should be able to get Isabelle +
  3426 Proof General to work in a plain Terminal after installing Poly/ML
  3427 (e.g. from the Isabelle distribution area) and GNU bash alone
  3428 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3429 support requires further installations, e.g. from
  3430 http://fink.sourceforge.net/);
  3431 
  3432 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3433 
  3434 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3435 of 40 MB), cf. ML_OPTIONS;
  3436 
  3437 * system: Proof General keywords specification is now part of the
  3438 Isabelle distribution (see etc/isar-keywords.el);
  3439 
  3440 * system: support for persistent Proof General sessions (refrain from
  3441 outdating all loaded theories on startup); user may create writable
  3442 logic images like this: ``isabelle -q HOL Test'';
  3443 
  3444 * system: smart selection of Isabelle process versus Isabelle
  3445 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3446 run both "isabelle" and "Isabelle" even if file names are badly
  3447 damaged (executable inspects the case of the first letter of its own
  3448 name); added separate "isabelle-process" and "isabelle-interface";
  3449 
  3450 * system: refrain from any attempt at filtering input streams; no
  3451 longer support ``8bit'' encoding of old isabelle font, instead proper
  3452 iso-latin characters may now be used; the related isatools
  3453 "symbolinput" and "nonascii" have disappeared as well;
  3454 
  3455 * system: removed old "xterm" interface (the print modes "xterm" and
  3456 "xterm_color" are still available for direct use in a suitable
  3457 terminal);
  3458 
  3459 
  3460 
  3461 New in Isabelle99-2 (February 2001)
  3462 -----------------------------------
  3463 
  3464 *** Overview of INCOMPATIBILITIES ***
  3465 
  3466 * HOL: please note that theories in the Library and elsewhere often use the
  3467 new-style (Isar) format; to refer to their theorems in an ML script you must
  3468 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3469 
  3470 * HOL: inductive package no longer splits induction rule aggressively,
  3471 but only as far as specified by the introductions given; the old
  3472 format may be recovered via ML function complete_split_rule or attribute
  3473 'split_rule (complete)';
  3474 
  3475 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3476 gfp_Tarski to gfp_unfold;
  3477 
  3478 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3479 
  3480 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3481 relation); infix "^^" has been renamed "``"; infix "``" has been
  3482 renamed "`"; "univalent" has been renamed "single_valued";
  3483 
  3484 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3485 operation;
  3486 
  3487 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3488 
  3489 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3490 
  3491 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3492 consequence, it is no longer monotonic wrt. the local goal context
  3493 (which is now passed through the inductive cases);
  3494 
  3495 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3496 \<gg> to \<ggreater>;
  3497 
  3498 
  3499 *** Document preparation ***
  3500 
  3501 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3502 available: are "it" for near math-mode best-style output, "sl" for
  3503 slanted text style, and "tt" for plain type-writer; if no
  3504 \isabellestyle command is given, output is according to slanted
  3505 type-writer);
  3506 
  3507 * support sub/super scripts (for single symbols only), input syntax is
  3508 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3509 
  3510 * some more standard symbols; see Appendix A of the system manual for
  3511 the complete list of symbols defined in isabellesym.sty;
  3512 
  3513 * improved isabelle style files; more abstract symbol implementation
  3514 (should now use \isamath{...} and \isatext{...} in custom symbol
  3515 definitions);
  3516 
  3517 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3518 state; Note that presentation of goal states does not conform to
  3519 actual human-readable proof documents.  Please do not include goal
  3520 states into document output unless you really know what you are doing!
  3521 
  3522 * proper indentation of antiquoted output with proportional LaTeX
  3523 fonts;
  3524 
  3525 * no_document ML operator temporarily disables LaTeX document
  3526 generation;
  3527 
  3528 * isatool unsymbolize tunes sources for plain ASCII communication;
  3529 
  3530 
  3531 *** Isar ***
  3532 
  3533 * Pure: Isar now suffers initial goal statements to contain unbound
  3534 schematic variables (this does not conform to actual readable proof
  3535 documents, due to unpredictable outcome and non-compositional proof
  3536 checking); users who know what they are doing may use schematic goals
  3537 for Prolog-style synthesis of proven results;
  3538 
  3539 * Pure: assumption method (an implicit finishing) now handles actual
  3540 rules as well;
  3541 
  3542 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3543 initial goal, declare "that" only as Pure intro (only for single
  3544 steps); the "that" rule assumption may now be involved in implicit
  3545 finishing, thus ".." becomes a feasible for trivial obtains;
  3546 
  3547 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3548 instance proofs may be performed by "..";
  3549 
  3550 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3551 statements as well;
  3552 
  3553 * Pure: more robust selection of calculational rules;
  3554 
  3555 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3556 rule (as well as the assumption rule);
  3557 
  3558 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3559 lemmas, using the graph browser tool;
  3560 
  3561 * Pure: predict failure of "show" in interactive mode;
  3562 
  3563 * Pure: 'thms_containing' now takes actual terms as arguments;
  3564 
  3565 * HOL: improved method 'induct' --- now handles non-atomic goals
  3566 (potential INCOMPATIBILITY); tuned error handling;
  3567 
  3568 * HOL: cases and induct rules now provide explicit hints about the
  3569 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3570 any remaining facts are inserted into the goal verbatim;
  3571 
  3572 * HOL: local contexts (aka cases) may now contain term bindings as
  3573 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3574 the result to be shown in each case;
  3575 
  3576 * HOL: added 'recdef_tc' command;
  3577 
  3578 * isatool convert assists in eliminating legacy ML scripts;
  3579 
  3580 
  3581 *** HOL ***
  3582 
  3583 * HOL/Library: a collection of generic theories to be used together
  3584 with main HOL; the theory loader path already includes this directory
  3585 by default; the following existing theories have been moved here:
  3586 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3587 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3588 
  3589 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3590 modelling and verification task performed in Isabelle/HOL +
  3591 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3592 
  3593 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3594 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3595 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3596 'domain', this makes the theory consistent with mathematical
  3597 literature;
  3598 
  3599 * HOL basics: added overloaded operations "inverse" and "divide"
  3600 (infix "/"), syntax for generic "abs" operation, generic summation
  3601 operator \<Sum>;
  3602 
  3603 * HOL/typedef: simplified package, provide more useful rules (see also
  3604 HOL/subset.thy);
  3605 
  3606 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3607 now expressed as a proper nested rule (old-style tactic scripts may
  3608 require atomize_strip_tac to cope with non-atomic premises);
  3609 
  3610 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3611 to "split_conv" (old name still available for compatibility);
  3612 
  3613 * HOL: improved concrete syntax for strings (e.g. allows translation
  3614 rules with string literals);
  3615 
  3616 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3617  and Fleuriot's mechanization of analysis, including the transcendental
  3618  functions for the reals;
  3619 
  3620 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3621 
  3622 
  3623 *** CTT ***
  3624 
  3625 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3626 "lam" is displayed as TWO lambda-symbols
  3627 
  3628 * CTT: theory Main now available, containing everything (that is, Bool
  3629 and Arith);
  3630 
  3631 
  3632 *** General ***
  3633 
  3634 * Pure: the Simplifier has been implemented properly as a derived rule
  3635 outside of the actual kernel (at last!); the overall performance
  3636 penalty in practical applications is about 50%, while reliability of
  3637 the Isabelle inference kernel has been greatly improved;
  3638 
  3639 * print modes "brackets" and "no_brackets" control output of nested =>
  3640 (types) and ==> (props); the default behaviour is "brackets";
  3641 
  3642 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3643 as assumptions as well;
  3644 
  3645 * system: support Poly/ML 4.0;
  3646 
  3647 * system: isatool install handles KDE version 1 or 2;
  3648 
  3649 
  3650 
  3651 New in Isabelle99-1 (October 2000)
  3652 ----------------------------------
  3653 
  3654 *** Overview of INCOMPATIBILITIES ***
  3655 
  3656 * HOL: simplification of natural numbers is much changed; to partly
  3657 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3658 issue the following ML commands:
  3659 
  3660   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3661   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3662 
  3663 * HOL: simplification no longer dives into case-expressions; this is
  3664 controlled by "t.weak_case_cong" for each datatype t;
  3665 
  3666 * HOL: nat_less_induct renamed to less_induct;
  3667 
  3668 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3669 fixsome to patch .thy and .ML sources automatically;
  3670 
  3671   select_equality  -> some_equality
  3672   select_eq_Ex     -> some_eq_ex
  3673   selectI2EX       -> someI2_ex
  3674   selectI2         -> someI2
  3675   selectI          -> someI
  3676   select1_equality -> some1_equality
  3677   Eps_sym_eq       -> some_sym_eq_trivial
  3678   Eps_eq           -> some_eq_trivial
  3679 
  3680 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3681 
  3682 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3683 instead);
  3684 
  3685 * HOL: the recursion equations generated by 'recdef' are now called
  3686 f.simps instead of f.rules;
  3687 
  3688 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3689 
  3690 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3691 sometimes be needed;
  3692 
  3693 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3694 
  3695 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3696 
  3697 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3698 product is now "<*>" instead of "Times"; the lexicographic product is
  3699 now "<*lex*>" instead of "**";
  3700 
  3701 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3702 of main HOL, but was unused); better use HOL's datatype package;
  3703 
  3704 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3705 the old syntax may be recovered as follows:
  3706 
  3707   syntax (symbols)
  3708     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3709       (infixl "\\<oplus>" 100)
  3710 
  3711 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3712 
  3713 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3714 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3715 internally;
  3716 
  3717 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3718 changed from A/r to A//r;
  3719 
  3720 * ZF: new treatment of arithmetic (nat & int) may break some old
  3721 proofs;
  3722 
  3723 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3724 rulify -> rule_format, elimify -> elim_format, ...);
  3725 
  3726 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3727 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3728 should have to change intro!! to intro? only); replaced "delrule" by
  3729 "rule del";
  3730 
  3731 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3732 
  3733 * Provers: strengthened force_tac by using new first_best_tac;
  3734 
  3735 * LaTeX document preparation: several changes of isabelle.sty (see
  3736 lib/texinputs);
  3737 
  3738 
  3739 *** Document preparation ***
  3740 
  3741 * formal comments (text blocks etc.) in new-style theories may now
  3742 contain antiquotations of thm/prop/term/typ/text to be presented
  3743 according to latex print mode; concrete syntax is like this:
  3744 @{term[show_types] "f(x) = a + x"};
  3745 
  3746 * isatool mkdir provides easy setup of Isabelle session directories,
  3747 including proper document sources;
  3748 
  3749 * generated LaTeX sources are now deleted after successful run
  3750 (isatool document -c); may retain a copy somewhere else via -D option
  3751 of isatool usedir;
  3752 
  3753 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3754 style files, achieving self-contained LaTeX sources and simplifying
  3755 LaTeX debugging;
  3756 
  3757 * old-style theories now produce (crude) LaTeX output as well;
  3758 
  3759 * browser info session directories are now self-contained (may be put
  3760 on WWW server seperately); improved graphs of nested sessions; removed
  3761 graph for 'all sessions';
  3762 
  3763 * several improvements in isabelle style files; \isabellestyle{it}
  3764 produces fake math mode output; \isamarkupheader is now \section by
  3765 default; see lib/texinputs/isabelle.sty etc.;
  3766 
  3767 
  3768 *** Isar ***
  3769 
  3770 * Isar/Pure: local results and corresponding term bindings are now
  3771 subject to Hindley-Milner polymorphism (similar to ML); this
  3772 accommodates incremental type-inference very nicely;
  3773 
  3774 * Isar/Pure: new derived language element 'obtain' supports
  3775 generalized existence reasoning;
  3776 
  3777 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3778 support accumulation of results, without applying any rules yet;
  3779 useful to collect intermediate results without explicit name
  3780 references, and for use with transitivity rules with more than 2
  3781 premises;
  3782 
  3783 * Isar/Pure: scalable support for case-analysis type proofs: new
  3784 'case' language element refers to local contexts symbolically, as
  3785 produced by certain proof methods; internally, case names are attached
  3786 to theorems as "tags";
  3787 
  3788 * Isar/Pure: theory command 'hide' removes declarations from
  3789 class/type/const name spaces;
  3790 
  3791 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3792 indicate potential overloading;
  3793 
  3794 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3795 
  3796 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3797 "{a,b,c}" instead of {a,b,c};
  3798 
  3799 * Isar/Pure now provides its own version of intro/elim/dest
  3800 attributes; useful for building new logics, but beware of confusion
  3801 with the version in Provers/classical;
  3802 
  3803 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3804 case name 'antecedent';
  3805 
  3806 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3807 to the current context is now done automatically);
  3808 
  3809 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3810 for definining proof methods in ML;
  3811 
  3812 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3813 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3814 most cases, one should have to change intro!! to intro? only);
  3815 replaced "delrule" by "rule del";
  3816 
  3817 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3818 'symmetric' attribute (the latter supercedes [RS sym]);
  3819 
  3820 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3821 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3822 well (including splits);
  3823 
  3824 * Isar/Provers: Simplifier and Classical methods now support all kind
  3825 of modifiers used in the past, including 'cong', 'iff', etc.
  3826 
  3827 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3828 of Simplifier and Classical reasoner);
  3829 
  3830 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3831 now support named cases; major packages (inductive, datatype, primrec,
  3832 recdef) support case names and properly name parameters;
  3833 
  3834 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3835 monotonicity conditions are extracted to be proven at end of
  3836 calculations;
  3837 
  3838 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3839 method anyway;
  3840 
  3841 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3842 split_if split_if_asm; datatype package provides theorems foo.splits =
  3843 foo.split foo.split_asm for each datatype;
  3844 
  3845 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3846 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3847 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3848 use "(cases (simplified))" method in proper proof texts);
  3849 
  3850 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3851 
  3852 * Isar: names of theorems etc. may be natural numbers as well;
  3853 
  3854 * Isar: 'pr' command: optional arguments for goals_limit and
  3855 ProofContext.prems_limit; no longer prints theory contexts, but only
  3856 proof states;
  3857 
  3858 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3859 additional print modes to be specified; e.g. "pr(latex)" will print
  3860 proof state according to the Isabelle LaTeX style;
  3861 
  3862 * Isar: improved support for emulating tactic scripts, including proof
  3863 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3864 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3865 (for HOL datatypes);
  3866 
  3867 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3868 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3869 'proof method scripts' have to be in depth-first order;
  3870 
  3871 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3872 
  3873 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3874 should instead use individual commands for printing items
  3875 (print_commands, print_methods etc.);
  3876 
  3877 * Isar: added 'nothing' --- the empty list of theorems;
  3878 
  3879 
  3880 *** HOL ***
  3881 
  3882 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3883 corresponding virtual machine and a specification of its bytecode
  3884 verifier and a lightweight bytecode verifier, including proofs of
  3885 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3886 Cornelia Pusch (see also the homepage of project Bali at
  3887 http://isabelle.in.tum.de/Bali/);
  3888 
  3889 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3890 Clemens Ballarin;
  3891 
  3892 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3893 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3894 Rasmussen;
  3895 
  3896 * HOL/Lattice: fundamental concepts of lattice theory and order
  3897 structures, including duals, properties of bounds versus algebraic
  3898 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3899 Theorem for complete lattices etc.; may also serve as a demonstration
  3900 for abstract algebraic reasoning using axiomatic type classes, and
  3901 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3902 
  3903 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3904 von Oheimb;
  3905 
  3906 * HOL/IMPP: extension of IMP with local variables and mutually
  3907 recursive procedures, by David von Oheimb;
  3908 
  3909 * HOL/Lambda: converted into new-style theory and document;
  3910 
  3911 * HOL/ex/Multiquote: example of multiple nested quotations and
  3912 anti-quotations -- basically a generalized version of de-Bruijn
  3913 representation; very useful in avoiding lifting of operations;
  3914 
  3915 * HOL/record: added general record equality rule to simpset; fixed
  3916 select-update simplification procedure to handle extended records as
  3917 well; admit "r" as field name;
  3918 
  3919 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3920 other numeric types and also as the identity of groups, rings, etc.;
  3921 
  3922 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3923 Types nat and int belong to this axclass;
  3924 
  3925 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3926    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3927    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3928   two terms #m*u and #n*u are replaced by #(m+n)*u
  3929     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3930   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3931     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3932 
  3933 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3934 powerful prover for predicate logic but knows nothing of clasets; see
  3935 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3936 
  3937 * HOL: new version of "case_tac" subsumes both boolean case split and
  3938 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3939 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3940 
  3941 * HOL: simplification no longer dives into case-expressions: only the
  3942 selector expression is simplified, but not the remaining arms; to
  3943 enable full simplification of case-expressions for datatype t, you may
  3944 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3945 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3946 
  3947 * HOL/recdef: the recursion equations generated by 'recdef' for
  3948 function 'f' are now called f.simps instead of f.rules; if all
  3949 termination conditions are proved automatically, these simplification
  3950 rules are added to the simpset, as in primrec; rules may be named
  3951 individually as well, resulting in a separate list of theorems for
  3952 each equation;
  3953 
  3954 * HOL/While is a new theory that provides a while-combinator. It
  3955 permits the definition of tail-recursive functions without the
  3956 provision of a termination measure. The latter is necessary once the
  3957 invariant proof rule for while is applied.
  3958 
  3959 * HOL: new (overloaded) notation for the set of elements below/above
  3960 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3961 
  3962 * HOL: theorems impI, allI, ballI bound as "strip";
  3963 
  3964 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3965 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3966 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3967 
  3968 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3969 
  3970 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3971 main HOL, but was unused);
  3972 
  3973 * HOL: fewer consts declared as global (e.g. have to refer to
  3974 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3975 
  3976 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3977 in case of overlap with user translations (e.g. judgements over
  3978 tuples); (note that the underlying logical represenation is still
  3979 bogus);
  3980 
  3981 
  3982 *** ZF ***
  3983 
  3984 * ZF: simplification automatically cancels common terms in arithmetic
  3985 expressions over nat and int;
  3986 
  3987 * ZF: new treatment of nat to minimize type-checking: all operators
  3988 coerce their operands to a natural number using the function natify,
  3989 making the algebraic laws unconditional;
  3990 
  3991 * ZF: as above, for int: operators coerce their operands to an integer
  3992 using the function intify;
  3993 
  3994 * ZF: the integer library now contains many of the usual laws for the
  3995 orderings, including $<=, and monotonicity laws for $+ and $*;
  3996 
  3997 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3998 simplification;
  3999 
  4000 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4001 to the simplifier and classical reasoner simultaneously;
  4002 
  4003 
  4004 *** General ***
  4005 
  4006 * Provers: blast_tac now handles actual object-logic rules as
  4007 assumptions; note that auto_tac uses blast_tac internally as well;
  4008 
  4009 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4010 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4011 
  4012 * Provers: delrules now handles destruct rules as well (no longer need
  4013 explicit make_elim);
  4014 
  4015 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4016   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4017 use instead the strong form,
  4018   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4019 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4020 from destruct-rules;
  4021 
  4022 * Provers: Simplifier.easy_setup provides a fast path to basic
  4023 Simplifier setup for new object-logics;
  4024 
  4025 * Pure: AST translation rules no longer require constant head on LHS;
  4026 
  4027 * Pure: improved name spaces: ambiguous output is qualified; support
  4028 for hiding of names;
  4029 
  4030 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4031 XSYMBOL_HOME; no longer need to do manual configuration in most
  4032 situations;
  4033 
  4034 * system: compression of ML heaps images may now be controlled via -c
  4035 option of isabelle and isatool usedir (currently only observed by
  4036 Poly/ML);
  4037 
  4038 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4039 useful for remote X11);
  4040 
  4041 * system: provide TAGS file for Isabelle sources;
  4042 
  4043 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4044 order;
  4045 
  4046 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4047 timing flag supersedes proof_timing and Toplevel.trace;
  4048 
  4049 * ML: new combinators |>> and |>>> for incremental transformations
  4050 with secondary results (e.g. certain theory extensions):
  4051 
  4052 * ML: PureThy.add_defs gets additional argument to indicate potential
  4053 overloading (usually false);
  4054 
  4055 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4056 results;
  4057 
  4058 
  4059 
  4060 New in Isabelle99 (October 1999)
  4061 --------------------------------
  4062 
  4063 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4064 
  4065 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4066 are no longer simplified.  (This allows the simplifier to unfold recursive
  4067 functional programs.)  To restore the old behaviour, declare
  4068 
  4069     Delcongs [if_weak_cong];
  4070 
  4071 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4072 complement;
  4073 
  4074 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4075 
  4076 * HOL/datatype: mutual_induct_tac no longer exists --
  4077   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4078 
  4079 * HOL/typedef: fixed type inference for representing set; type
  4080 arguments now have to occur explicitly on the rhs as type constraints;
  4081 
  4082 * ZF: The con_defs part of an inductive definition may no longer refer
  4083 to constants declared in the same theory;
  4084 
  4085 * HOL, ZF: the function mk_cases, generated by the inductive
  4086 definition package, has lost an argument.  To simplify its result, it
  4087 uses the default simpset instead of a supplied list of theorems.
  4088 
  4089 * HOL/List: the constructors of type list are now Nil and Cons;
  4090 
  4091 * Simplifier: the type of the infix ML functions
  4092         setSSolver addSSolver setSolver addSolver
  4093 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4094 for packaging solvers. A solver is created via
  4095         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4096 where the string argument is only a comment.
  4097 
  4098 
  4099 *** Proof tools ***
  4100 
  4101 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4102 decision procedure for linear arithmetic. Currently it is used for
  4103 types `nat', `int', and `real' in HOL (see below); it can, should and
  4104 will be instantiated for other types and logics as well.
  4105 
  4106 * The simplifier now accepts rewrite rules with flexible heads, eg
  4107      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4108   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4109   matching.
  4110 
  4111 
  4112 *** General ***
  4113 
  4114 * New Isabelle/Isar subsystem provides an alternative to traditional
  4115 tactical theorem proving; together with the ProofGeneral/isar user
  4116 interface it offers an interactive environment for developing human
  4117 readable proof documents (Isar == Intelligible semi-automated
  4118 reasoning); for further information see isatool doc isar-ref,
  4119 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4120 
  4121 * improved and simplified presentation of theories: better HTML markup
  4122 (including colors), graph views in several sizes; isatool usedir now
  4123 provides a proper interface for user theories (via -P option); actual
  4124 document preparation based on (PDF)LaTeX is available as well (for
  4125 new-style theories only); see isatool doc system for more information;
  4126 
  4127 * native support for Proof General, both for classic Isabelle and
  4128 Isabelle/Isar;
  4129 
  4130 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4131 using the graph browser tool;
  4132 
  4133 * Isabelle manuals now also available as PDF;
  4134 
  4135 * theory loader rewritten from scratch (may not be fully
  4136 bug-compatible); old loadpath variable has been replaced by show_path,
  4137 add_path, del_path, reset_path functions; new operations such as
  4138 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4139 isatool doc ref);
  4140 
  4141 * improved isatool install: option -k creates KDE application icon,
  4142 option -p DIR installs standalone binaries;
  4143 
  4144 * added ML_PLATFORM setting (useful for cross-platform installations);
  4145 more robust handling of platform specific ML images for SML/NJ;
  4146 
  4147 * the settings environment is now statically scoped, i.e. it is never
  4148 created again in sub-processes invoked from isabelle, isatool, or
  4149 Isabelle;
  4150 
  4151 * path element specification '~~' refers to '$ISABELLE_HOME';
  4152 
  4153 * in locales, the "assumes" and "defines" parts may be omitted if
  4154 empty;
  4155 
  4156 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4157 long arrows);
  4158 
  4159 * new print_mode "HTML";
  4160 
  4161 * new flag show_tags controls display of tags of theorems (which are
  4162 basically just comments that may be attached by some tools);
  4163 
  4164 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4165 mode and goal output format:
  4166 
  4167 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4168 244c244
  4169 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4170 ---
  4171 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4172 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4173 181c181
  4174 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4175 ---
  4176 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4177 
  4178 * function bind_thms stores lists of theorems (cf. bind_thm);
  4179 
  4180 * new shorthand tactics ftac, eatac, datac, fatac;
  4181 
  4182 * qed (and friends) now accept "" as result name; in that case the
  4183 theorem is not stored, but proper checks and presentation of the
  4184 result still apply;
  4185 
  4186 * theorem database now also indexes constants "Trueprop", "all",
  4187 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4188 
  4189 
  4190 *** HOL ***
  4191 
  4192 ** HOL arithmetic **
  4193 
  4194 * There are now decision procedures for linear arithmetic over nat and
  4195 int:
  4196 
  4197 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4198 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4199 are treated as atomic; subformulae not involving type `nat' or `int'
  4200 are ignored; quantified subformulae are ignored unless they are
  4201 positive universal or negative existential. The tactic has to be
  4202 invoked by hand and can be a little bit slow. In particular, the
  4203 running time is exponential in the number of occurrences of `min' and
  4204 `max', and `-' on `nat'.
  4205 
  4206 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4207 (negated) (in)equalities among the premises and the conclusion into
  4208 account (i.e. no compound formulae) and does not know about `min' and
  4209 `max', and `-' on `nat'. It is fast and is used automatically by the
  4210 simplifier.
  4211 
  4212 NB: At the moment, these decision procedures do not cope with mixed
  4213 nat/int formulae where the two parts interact, such as `m < n ==>
  4214 int(m) < int(n)'.
  4215 
  4216 * HOL/Numeral provides a generic theory of numerals (encoded
  4217 efficiently as bit strings); setup for types nat/int/real is in place;
  4218 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4219 int, existing theories and proof scripts may require a few additional
  4220 type constraints;
  4221 
  4222 * integer division and remainder can now be performed on constant
  4223 arguments;
  4224 
  4225 * many properties of integer multiplication, division and remainder
  4226 are now available;
  4227 
  4228 * An interface to the Stanford Validity Checker (SVC) is available through the
  4229 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4230 are proved automatically.  SVC must be installed separately, and its results
  4231 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4232 invocation of the underlying oracle).  For SVC see
  4233   http://verify.stanford.edu/SVC
  4234 
  4235 * IsaMakefile: the HOL-Real target now builds an actual image;
  4236 
  4237 
  4238 ** HOL misc **
  4239 
  4240 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4241 (in Isabelle/Isar) -- by Gertrud Bauer;
  4242 
  4243 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4244 analysis for assembly languages with subtypes;
  4245 
  4246 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4247 -- avoids syntactic ambiguities and treats state, transition, and
  4248 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4249 changed syntax and (many) tactics;
  4250 
  4251 * HOL/inductive: Now also handles more general introduction rules such
  4252   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4253   theorems are now maintained within the theory (maintained via the
  4254   "mono" attribute);
  4255 
  4256 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4257   (using function types) such as
  4258 
  4259   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4260 
  4261 * HOL/record: record_simproc (part of the default simpset) takes care
  4262 of selectors applied to updated records; record_split_tac is no longer
  4263 part of the default claset; update_defs may now be removed from the
  4264 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4265 
  4266   claset_ref () := claset() addSWrapper record_split_wrapper;
  4267   Delsimprocs [record_simproc]
  4268 
  4269 * HOL/typedef: fixed type inference for representing set; type
  4270 arguments now have to occur explicitly on the rhs as type constraints;
  4271 
  4272 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4273 names rather than an ML expression;
  4274 
  4275 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4276 supplied later.  Program schemes can be defined, such as
  4277     "While B C s = (if B s then While B C (C s) else s)"
  4278 where the well-founded relation can be chosen after B and C have been given.
  4279 
  4280 * HOL/List: the constructors of type list are now Nil and Cons;
  4281 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4282 course, ML tools referring to List.list.op # etc. have to be adapted;
  4283 
  4284 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4285 disabled by default; run isabelle with option -m HOL to get back to
  4286 the original Gordon/HOL-style output;
  4287 
  4288 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4289 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4290 
  4291 * HOL basic syntax simplified (more orthogonal): all variants of
  4292 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4293 Eps operator is provided as well: "SOME x. P[x]";
  4294 
  4295 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4296 
  4297 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4298 thus available for user theories;
  4299 
  4300 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4301 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4302 time;
  4303 
  4304 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4305 several times and then mp;
  4306 
  4307 
  4308 *** LK ***
  4309 
  4310 * the notation <<...>> is now available as a notation for sequences of
  4311 formulas;
  4312 
  4313 * the simplifier is now installed
  4314 
  4315 * the axiom system has been generalized (thanks to Soren Heilmann)
  4316 
  4317 * the classical reasoner now has a default rule database
  4318 
  4319 
  4320 *** ZF ***
  4321 
  4322 * new primrec section allows primitive recursive functions to be given
  4323 directly (as in HOL) over datatypes and the natural numbers;
  4324 
  4325 * new tactics induct_tac and exhaust_tac for induction (or case
  4326 analysis) over datatypes and the natural numbers;
  4327 
  4328 * the datatype declaration of type T now defines the recursor T_rec;
  4329 
  4330 * simplification automatically does freeness reasoning for datatype
  4331 constructors;
  4332 
  4333 * automatic type-inference, with AddTCs command to insert new
  4334 type-checking rules;
  4335 
  4336 * datatype introduction rules are now added as Safe Introduction rules
  4337 to the claset;
  4338 
  4339 * the syntax "if P then x else y" is now available in addition to
  4340 if(P,x,y);
  4341 
  4342 
  4343 *** Internal programming interfaces ***
  4344 
  4345 * tuned simplifier trace output; new flag debug_simp;
  4346 
  4347 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4348 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4349 
  4350 * AxClass.axclass_tac lost the theory argument;
  4351 
  4352 * tuned current_goals_markers semantics: begin / end goal avoids
  4353 printing empty lines;
  4354 
  4355 * removed prs and prs_fn hook, which was broken because it did not
  4356 include \n in its semantics, forcing writeln to add one
  4357 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4358 string -> unit if you really want to output text without newline;
  4359 
  4360 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4361 plain output, interface builders may have to enable 'isabelle_font'
  4362 mode to get Isabelle font glyphs as before;
  4363 
  4364 * refined token_translation interface; INCOMPATIBILITY: output length
  4365 now of type real instead of int;
  4366 
  4367 * theory loader actions may be traced via new ThyInfo.add_hook
  4368 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4369 your own database of information attached to *whole* theories -- as
  4370 opposed to intra-theory data slots offered via TheoryDataFun;
  4371 
  4372 * proper handling of dangling sort hypotheses (at last!);
  4373 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4374 extra sort hypotheses that can be witnessed from the type signature;
  4375 the force_strip_shyps flag is gone, any remaining shyps are simply
  4376 left in the theorem (with a warning issued by strip_shyps_warning);
  4377 
  4378 
  4379 
  4380 New in Isabelle98-1 (October 1998)
  4381 ----------------------------------
  4382 
  4383 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4384 
  4385 * several changes of automated proof tools;
  4386 
  4387 * HOL: major changes to the inductive and datatype packages, including
  4388 some minor incompatibilities of theory syntax;
  4389 
  4390 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4391 called `inj_on';
  4392 
  4393 * HOL: removed duplicate thms in Arith:
  4394   less_imp_add_less  should be replaced by  trans_less_add1
  4395   le_imp_add_le      should be replaced by  trans_le_add1
  4396 
  4397 * HOL: unary minus is now overloaded (new type constraints may be
  4398 required);
  4399 
  4400 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4401 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4402 now taken as an integer constant.
  4403 
  4404 * Pure: ML function 'theory_of' renamed to 'theory';
  4405 
  4406 
  4407 *** Proof tools ***
  4408 
  4409 * Simplifier:
  4410   1. Asm_full_simp_tac is now more aggressive.
  4411      1. It will sometimes reorient premises if that increases their power to
  4412         simplify.
  4413      2. It does no longer proceed strictly from left to right but may also
  4414         rotate premises to achieve further simplification.
  4415      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4416      old Asm_full_simp_tac in that it does not rotate premises.
  4417   2. The simplifier now knows a little bit about nat-arithmetic.
  4418 
  4419 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4420 allows for selected deletion of wrappers, by introduction of names for
  4421 wrapper functionals.  This implies that addbefore, addSbefore,
  4422 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4423 and that adding two tactics with the same name overwrites the first
  4424 one (emitting a warning).
  4425   type wrapper = (int -> tactic) -> (int -> tactic)
  4426   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4427   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4428   delWrapper, delSWrapper: claset *  string            -> claset
  4429   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4430 
  4431 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4432 semantics; addbefore now affects only the unsafe part of step_tac
  4433 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4434 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4435 by Force_tac;
  4436 
  4437 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4438 compWrapper; added safe wrapper (and access functions for it);
  4439 
  4440 * HOL/split_all_tac is now much faster and fails if there is nothing
  4441 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4442 and the names of the automatically generated variables have changed.
  4443 split_all_tac has moved within claset() from unsafe wrappers to safe
  4444 wrappers, which means that !!-bound variables are split much more
  4445 aggressively, and safe_tac and clarify_tac now split such variables.
  4446 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4447 Note: the same holds for record_split_tac, which does the job of
  4448 split_all_tac for record fields.
  4449 
  4450 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4451 permanently to the default simpset using Addsplits just like
  4452 Addsimps. They can be removed via Delsplits just like
  4453 Delsimps. Lower-case versions are also available.
  4454 
  4455 * HOL/Simplifier: The rule split_if is now part of the default
  4456 simpset. This means that the simplifier will eliminate all occurrences
  4457 of if-then-else in the conclusion of a goal. To prevent this, you can
  4458 either remove split_if completely from the default simpset by
  4459 `Delsplits [split_if]' or remove it in a specific call of the
  4460 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4461 other case splitting rules to/from the default simpset: every datatype
  4462 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4463 t is the name of the datatype).
  4464 
  4465 * Classical reasoner / Simplifier combination: new force_tac (and
  4466 derivatives Force_tac, force) combines rewriting and classical
  4467 reasoning (and whatever other tools) similarly to auto_tac, but is
  4468 aimed to solve the given subgoal completely.
  4469 
  4470 
  4471 *** General ***
  4472 
  4473 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4474 and `goalw': the theory is no longer needed as an explicit argument -
  4475 the current theory context is used; assumptions are no longer returned
  4476 at the ML-level unless one of them starts with ==> or !!; it is
  4477 recommended to convert to these new commands using isatool fixgoal
  4478 (backup your sources first!);
  4479 
  4480 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4481 the current theory context, and 'theory' to lookup stored theories;
  4482 
  4483 * new theory section 'locale' for declaring constants, assumptions and
  4484 definitions that have local scope;
  4485 
  4486 * new theory section 'nonterminals' for purely syntactic types;
  4487 
  4488 * new theory section 'setup' for generic ML setup functions
  4489 (e.g. package initialization);
  4490 
  4491 * the distribution now includes Isabelle icons: see
  4492 lib/logo/isabelle-{small,tiny}.xpm;
  4493 
  4494 * isatool install - install binaries with absolute references to
  4495 ISABELLE_HOME/bin;
  4496 
  4497 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4498 
  4499 * print mode 'emacs' reserved for Isamode;
  4500 
  4501 * support multiple print (ast) translations per constant name;
  4502 
  4503 * theorems involving oracles are now printed with a suffixed [!];
  4504 
  4505 
  4506 *** HOL ***
  4507 
  4508 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4509 
  4510 * HOL/inductive package reorganized and improved: now supports mutual
  4511 definitions such as
  4512 
  4513   inductive EVEN ODD
  4514     intrs
  4515       null "0 : EVEN"
  4516       oddI "n : EVEN ==> Suc n : ODD"
  4517       evenI "n : ODD ==> Suc n : EVEN"
  4518 
  4519 new theorem list "elims" contains an elimination rule for each of the
  4520 recursive sets; inductive definitions now handle disjunctive premises
  4521 correctly (also ZF);
  4522 
  4523 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4524 "mutual_induct" no longer exists - the induction rule is always
  4525 contained in "induct";
  4526 
  4527 
  4528 * HOL/datatype package re-implemented and greatly improved: now
  4529 supports mutually recursive datatypes such as
  4530 
  4531   datatype
  4532     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4533             | SUM ('a aexp) ('a aexp)
  4534             | DIFF ('a aexp) ('a aexp)
  4535             | NUM 'a
  4536   and
  4537     'a bexp = LESS ('a aexp) ('a aexp)
  4538             | AND ('a bexp) ('a bexp)
  4539             | OR ('a bexp) ('a bexp)
  4540 
  4541 as well as indirectly recursive datatypes such as
  4542 
  4543   datatype
  4544     ('a, 'b) term = Var 'a
  4545                   | App 'b ((('a, 'b) term) list)
  4546 
  4547 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4548 induction on mutually / indirectly recursive datatypes.
  4549 
  4550 Primrec equations are now stored in theory and can be accessed via
  4551 <function_name>.simps.
  4552 
  4553 INCOMPATIBILITIES:
  4554 
  4555   - Theories using datatypes must now have theory Datatype as an
  4556     ancestor.
  4557   - The specific <typename>.induct_tac no longer exists - use the
  4558     generic induct_tac instead.
  4559   - natE has been renamed to nat.exhaust - use exhaust_tac
  4560     instead of res_inst_tac ... natE. Note that the variable
  4561     names in nat.exhaust differ from the names in natE, this
  4562     may cause some "fragile" proofs to fail.
  4563   - The theorems split_<typename>_case and split_<typename>_case_asm
  4564     have been renamed to <typename>.split and <typename>.split_asm.
  4565   - Since default sorts of type variables are now handled correctly,
  4566     some datatype definitions may have to be annotated with explicit
  4567     sort constraints.
  4568   - Primrec definitions no longer require function name and type
  4569     of recursive argument.
  4570 
  4571 Consider using isatool fixdatatype to adapt your theories and proof
  4572 scripts to the new package (backup your sources first!).
  4573 
  4574 
  4575 * HOL/record package: considerably improved implementation; now
  4576 includes concrete syntax for record types, terms, updates; theorems
  4577 for surjective pairing and splitting !!-bound record variables; proof
  4578 support is as follows:
  4579 
  4580   1) standard conversions (selectors or updates applied to record
  4581 constructor terms) are part of the standard simpset;
  4582 
  4583   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4584 made part of standard simpset and claset via addIffs;
  4585 
  4586   3) a tactic for record field splitting (record_split_tac) is part of
  4587 the standard claset (addSWrapper);
  4588 
  4589 To get a better idea about these rules you may retrieve them via
  4590 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4591 the name of your record type.
  4592 
  4593 The split tactic 3) conceptually simplifies by the following rule:
  4594 
  4595   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4596 
  4597 Thus any record variable that is bound by meta-all will automatically
  4598 blow up into some record constructor term, consequently the
  4599 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4600 solve record problems automatically.
  4601 
  4602 
  4603 * reorganized the main HOL image: HOL/Integ and String loaded by
  4604 default; theory Main includes everything;
  4605 
  4606 * automatic simplification of integer sums and comparisons, using cancellation;
  4607 
  4608 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4609 
  4610 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4611 
  4612 * many new identities for unions, intersections, set difference, etc.;
  4613 
  4614 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4615 called split_if, split_split, split_sum_case and split_nat_case (to go
  4616 with add/delsplits);
  4617 
  4618 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4619 (?x::unit) = (); this is made part of the default simpset, which COULD
  4620 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4621 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4622 unit_abs_eta_conv is added in order to counter the effect of
  4623 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4624 %u.f();
  4625 
  4626 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4627 makes more sense);
  4628 
  4629 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4630   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4631   disjointness reasoning but breaking a few old proofs.
  4632 
  4633 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4634 to 'converse' from 'inverse' (for compatibility with ZF and some
  4635 literature);
  4636 
  4637 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4638 the well-founded relation;
  4639 
  4640 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4641     Compl A.  The "Compl" syntax remains available as input syntax for this
  4642     release ONLY.
  4643 
  4644 * HOL/Update: new theory of function updates:
  4645     f(a:=b) == %x. if x=a then b else f x
  4646 may also be iterated as in f(a:=b,c:=d,...);
  4647 
  4648 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4649 
  4650 * HOL/List:
  4651   - new function list_update written xs[i:=v] that updates the i-th
  4652     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4653   - new function `upt' written [i..j(] which generates the list
  4654     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4655     bound write [i..j], which is a shorthand for [i..j+1(].
  4656   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4657 
  4658 * HOL/Arith:
  4659   - removed 'pred' (predecessor) function;
  4660   - generalized some theorems about n-1;
  4661   - many new laws about "div" and "mod";
  4662   - new laws about greatest common divisors (see theory ex/Primes);
  4663 
  4664 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4665 instead of "inverse";
  4666 
  4667 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4668   of the multiset ordering;
  4669 
  4670 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4671   (not included by default);
  4672 
  4673 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4674 
  4675 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4676   programs, i.e. different program variables may have different types.
  4677 
  4678 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4679   [previously, this check worked only if the rewrite rule was unconditional]
  4680   Now rew can involve either definitions or equalities (either == or =).
  4681 
  4682 
  4683 *** ZF ***
  4684 
  4685 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4686   only the theorems proved on ZF.ML;
  4687 
  4688 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4689   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4690   disjointness reasoning but breaking a few old proofs.
  4691 
  4692 * ZF/Update: new theory of function updates
  4693     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4694   may also be iterated as in f(a:=b,c:=d,...);
  4695 
  4696 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4697 
  4698 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4699   [previously, this check worked only if the rewrite rule was unconditional]
  4700   Now rew can involve either definitions or equalities (either == or =).
  4701 
  4702 * case_tac provided for compatibility with HOL
  4703     (like the old excluded_middle_tac, but with subgoals swapped)
  4704 
  4705 
  4706 *** Internal programming interfaces ***
  4707 
  4708 * Pure: several new basic modules made available for general use, see
  4709 also src/Pure/README;
  4710 
  4711 * improved the theory data mechanism to support encapsulation (data
  4712 kind name replaced by private Object.kind, acting as authorization
  4713 key); new type-safe user interface via functor TheoryDataFun; generic
  4714 print_data function becomes basically useless;
  4715 
  4716 * removed global_names compatibility flag -- all theory declarations
  4717 are qualified by default;
  4718 
  4719 * module Pure/Syntax now offers quote / antiquote translation
  4720 functions (useful for Hoare logic etc. with implicit dependencies);
  4721 see HOL/ex/Antiquote for an example use;
  4722 
  4723 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4724 cterm -> thm;
  4725 
  4726 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4727 subgoal;
  4728 
  4729 * Display.print_goals function moved to Locale.print_goals;
  4730 
  4731 * standard print function for goals supports current_goals_markers
  4732 variable for marking begin of proof, end of proof, start of goal; the
  4733 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4734 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4735 for example;
  4736 
  4737 
  4738 
  4739 New in Isabelle98 (January 1998)
  4740 --------------------------------
  4741 
  4742 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4743 
  4744 * changed lexical syntax of terms / types: dots made part of long
  4745 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4746 
  4747 * simpset (and claset) reference variable replaced by functions
  4748 simpset / simpset_ref;
  4749 
  4750 * no longer supports theory aliases (via merge) and non-trivial
  4751 implicit merge of thms' signatures;
  4752 
  4753 * most internal names of constants changed due to qualified names;
  4754 
  4755 * changed Pure/Sequence interface (see Pure/seq.ML);
  4756 
  4757 
  4758 *** General Changes ***
  4759 
  4760 * hierachically structured name spaces (for consts, types, axms, thms
  4761 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4762 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4763 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4764 long_names for fully qualified output names; NOTE: ML programs
  4765 (special tactics, packages etc.) referring to internal names may have
  4766 to be adapted to cope with fully qualified names; in case of severe
  4767 backward campatibility problems try setting 'global_names' at compile
  4768 time to have enrything declared within a flat name space; one may also
  4769 fine tune name declarations in theories via the 'global' and 'local'
  4770 section;
  4771 
  4772 * reimplemented the implicit simpset and claset using the new anytype
  4773 data filed in signatures; references simpset:simpset ref etc. are
  4774 replaced by functions simpset:unit->simpset and
  4775 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4776 to patch your ML files accordingly;
  4777 
  4778 * HTML output now includes theory graph data for display with Java
  4779 applet or isatool browser; data generated automatically via isatool
  4780 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4781 
  4782 * defs may now be conditional; improved rewrite_goals_tac to handle
  4783 conditional equations;
  4784 
  4785 * defs now admits additional type arguments, using TYPE('a) syntax;
  4786 
  4787 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4788 creates a new theory node; implicit merge of thms' signatures is
  4789 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4790 transfer:theory->thm->thm in (rare) cases;
  4791 
  4792 * improved handling of draft signatures / theories; draft thms (and
  4793 ctyps, cterms) are automatically promoted to real ones;
  4794 
  4795 * slightly changed interfaces for oracles: admit many per theory, named
  4796 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4797 
  4798 * print_goals: optional output of const types (set show_consts and
  4799 show_types);
  4800 
  4801 * improved output of warnings (###) and errors (***);
  4802 
  4803 * subgoal_tac displays a warning if the new subgoal has type variables;
  4804 
  4805 * removed old README and Makefiles;
  4806 
  4807 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4808 
  4809 * removed obsolete init_pps and init_database;
  4810 
  4811 * deleted the obsolete tactical STATE, which was declared by
  4812     fun STATE tacfun st = tacfun st st;
  4813 
  4814 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4815 (which abbreviates $HOME);
  4816 
  4817 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4818 use isatool fixseq to adapt your ML programs (this works for fully
  4819 qualified references to the Sequence structure only!);
  4820 
  4821 * use_thy no longer requires writable current directory; it always
  4822 reloads .ML *and* .thy file, if either one is out of date;
  4823 
  4824 
  4825 *** Classical Reasoner ***
  4826 
  4827 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4828 tactics that use classical reasoning to simplify a subgoal without
  4829 splitting it into several subgoals;
  4830 
  4831 * Safe_tac: like safe_tac but uses the default claset;
  4832 
  4833 
  4834 *** Simplifier ***
  4835 
  4836 * added simplification meta rules:
  4837     (asm_)(full_)simplify: simpset -> thm -> thm;
  4838 
  4839 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4840 logics (again);
  4841 
  4842 * added prems argument to simplification procedures;
  4843 
  4844 * HOL, FOL, ZF: added infix function `addsplits':
  4845   instead of `<simpset> setloop (split_tac <thms>)'
  4846   you can simply write `<simpset> addsplits <thms>'
  4847 
  4848 
  4849 *** Syntax ***
  4850 
  4851 * TYPE('a) syntax for type reflection terms;
  4852 
  4853 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4854 
  4855 * pretty printer: changed order of mixfix annotation preference (again!);
  4856 
  4857 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4858 
  4859 
  4860 *** HOL ***
  4861 
  4862 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4863   with `addloop' of the simplifier to faciliate case splitting in premises.
  4864 
  4865 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4866 
  4867 * HOL/Auth: new protocol proofs including some for the Internet
  4868   protocol TLS;
  4869 
  4870 * HOL/Map: new theory of `maps' a la VDM;
  4871 
  4872 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4873 cancelling out common nat summands from =, <, <= (in)equalities, or
  4874 differences; simplification procedures nat_cancel_factor for
  4875 cancelling common factor from =, <, <= (in)equalities over natural
  4876 sums; nat_cancel contains both kinds of procedures, it is installed by
  4877 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4878 
  4879 * HOL/simplifier: terms of the form
  4880   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4881   are rewritten to
  4882   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4883   and those of the form
  4884   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4885   are rewritten to
  4886   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4887 
  4888 * HOL/datatype
  4889   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4890 
  4891   P(t_case f1 ... fn x) =
  4892      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4893         ...
  4894        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4895      )
  4896 
  4897   and a theorem `split_t_case_asm' of the form
  4898 
  4899   P(t_case f1 ... fn x) =
  4900     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4901         ...
  4902        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4903      )
  4904   which can be added to a simpset via `addsplits'. The existing theorems
  4905   expand_list_case and expand_option_case have been renamed to
  4906   split_list_case and split_option_case.
  4907 
  4908 * HOL/Arithmetic:
  4909   - `pred n' is automatically converted to `n-1'.
  4910     Users are strongly encouraged not to use `pred' any longer,
  4911     because it will disappear altogether at some point.
  4912   - Users are strongly encouraged to write "0 < n" rather than
  4913     "n ~= 0". Theorems and proof tools have been modified towards this
  4914     `standard'.
  4915 
  4916 * HOL/Lists:
  4917   the function "set_of_list" has been renamed "set" (and its theorems too);
  4918   the function "nth" now takes its arguments in the reverse order and
  4919   has acquired the infix notation "!" as in "xs!n".
  4920 
  4921 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4922 
  4923 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4924   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4925 
  4926 * HOL/record: extensible records with schematic structural subtyping
  4927 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4928 still lacks various theorems and concrete record syntax;
  4929 
  4930 
  4931 *** HOLCF ***
  4932 
  4933 * removed "axioms" and "generated by" sections;
  4934 
  4935 * replaced "ops" section by extended "consts" section, which is capable of
  4936   handling the continuous function space "->" directly;
  4937 
  4938 * domain package:
  4939   . proves theorems immediately and stores them in the theory,
  4940   . creates hierachical name space,
  4941   . now uses normal mixfix annotations (instead of cinfix...),
  4942   . minor changes to some names and values (for consistency),
  4943   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4944   . separator between mutual domain defs: changed "," to "and",
  4945   . improved handling of sort constraints;  now they have to
  4946     appear on the left-hand side of the equations only;
  4947 
  4948 * fixed LAM <x,y,zs>.b syntax;
  4949 
  4950 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4951 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4952 
  4953 
  4954 *** FOL and ZF ***
  4955 
  4956 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4957   with `addloop' of the simplifier to faciliate case splitting in premises.
  4958 
  4959 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4960 in HOL, they strip ALL and --> from proved theorems;
  4961 
  4962 
  4963 
  4964 New in Isabelle94-8 (May 1997)
  4965 ------------------------------
  4966 
  4967 *** General Changes ***
  4968 
  4969 * new utilities to build / run / maintain Isabelle etc. (in parts
  4970 still somewhat experimental); old Makefiles etc. still functional;
  4971 
  4972 * new 'Isabelle System Manual';
  4973 
  4974 * INSTALL text, together with ./configure and ./build scripts;
  4975 
  4976 * reimplemented type inference for greater efficiency, better error
  4977 messages and clean internal interface;
  4978 
  4979 * prlim command for dealing with lots of subgoals (an easier way of
  4980 setting goals_limit);
  4981 
  4982 
  4983 *** Syntax ***
  4984 
  4985 * supports alternative (named) syntax tables (parser and pretty
  4986 printer); internal interface is provided by add_modesyntax(_i);
  4987 
  4988 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4989 be used in conjunction with the Isabelle symbol font; uses the
  4990 "symbols" syntax table;
  4991 
  4992 * added token_translation interface (may translate name tokens in
  4993 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4994 the current print_mode); IMPORTANT: user print translation functions
  4995 are responsible for marking newly introduced bounds
  4996 (Syntax.mark_boundT);
  4997 
  4998 * token translations for modes "xterm" and "xterm_color" that display
  4999 names in bold, underline etc. or colors (which requires a color
  5000 version of xterm);
  5001 
  5002 * infixes may now be declared with names independent of their syntax;
  5003 
  5004 * added typed_print_translation (like print_translation, but may
  5005 access type of constant);
  5006 
  5007 
  5008 *** Classical Reasoner ***
  5009 
  5010 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5011 some limitations.  Blast_tac...
  5012   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5013   + ignores elimination rules that don't have the correct format
  5014         (the conclusion MUST be a formula variable)
  5015   + ignores types, which can make HOL proofs fail
  5016   + rules must not require higher-order unification, e.g. apply_type in ZF
  5017     [message "Function Var's argument not a bound variable" relates to this]
  5018   + its proof strategy is more general but can actually be slower
  5019 
  5020 * substitution with equality assumptions no longer permutes other
  5021 assumptions;
  5022 
  5023 * minor changes in semantics of addafter (now called addaltern); renamed
  5024 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5025 (and access functions for it);
  5026 
  5027 * improved combination of classical reasoner and simplifier:
  5028   + functions for handling clasimpsets
  5029   + improvement of addss: now the simplifier is called _after_ the
  5030     safe steps.
  5031   + safe variant of addss called addSss: uses safe simplifications
  5032     _during_ the safe steps. It is more complete as it allows multiple
  5033     instantiations of unknowns (e.g. with slow_tac).
  5034 
  5035 *** Simplifier ***
  5036 
  5037 * added interface for simplification procedures (functions that
  5038 produce *proven* rewrite rules on the fly, depending on current
  5039 redex);
  5040 
  5041 * ordering on terms as parameter (used for ordered rewriting);
  5042 
  5043 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5044 
  5045 * the solver is now split into a safe and an unsafe part.
  5046 This should be invisible for the normal user, except that the
  5047 functions setsolver and addsolver have been renamed to setSolver and
  5048 addSolver; added safe_asm_full_simp_tac;
  5049 
  5050 
  5051 *** HOL ***
  5052 
  5053 * a generic induction tactic `induct_tac' which works for all datatypes and
  5054 also for type `nat';
  5055 
  5056 * a generic case distinction tactic `exhaust_tac' which works for all
  5057 datatypes and also for type `nat';
  5058 
  5059 * each datatype comes with a function `size';
  5060 
  5061 * patterns in case expressions allow tuple patterns as arguments to
  5062 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5063 
  5064 * primrec now also works with type nat;
  5065 
  5066 * recdef: a new declaration form, allows general recursive functions to be
  5067 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5068 
  5069 * the constant for negation has been renamed from "not" to "Not" to
  5070 harmonize with FOL, ZF, LK, etc.;
  5071 
  5072 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5073 infinite lists;
  5074 
  5075 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5076 
  5077 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5078 problems in commutative rings, using axiomatic type classes for + and *;
  5079 
  5080 * more examples in HOL/MiniML and HOL/Auth;
  5081 
  5082 * more default rewrite rules for quantifiers, union/intersection;
  5083 
  5084 * a new constant `arbitrary == @x.False';
  5085 
  5086 * HOLCF/IOA replaces old HOL/IOA;
  5087 
  5088 * HOLCF changes: derived all rules and arities
  5089   + axiomatic type classes instead of classes
  5090   + typedef instead of faking type definitions
  5091   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5092   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5093   + eliminated the types void, one, tr
  5094   + use unit lift and bool lift (with translations) instead of one and tr
  5095   + eliminated blift from Lift3.thy (use Def instead of blift)
  5096   all eliminated rules are derived as theorems --> no visible changes ;
  5097 
  5098 
  5099 *** ZF ***
  5100 
  5101 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5102 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5103 as ZF_cs addSIs [equalityI];
  5104 
  5105 
  5106 
  5107 New in Isabelle94-7 (November 96)
  5108 ---------------------------------
  5109 
  5110 * allowing negative levels (as offsets) in prlev and choplev;
  5111 
  5112 * super-linear speedup for large simplifications;
  5113 
  5114 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5115 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5116 FAIL); can suppress it using the command Delsimps (ex_simps @
  5117 all_simps); De Morgan laws are also now included, by default;
  5118 
  5119 * improved printing of ==>  :  ~:
  5120 
  5121 * new object-logic "Sequents" adds linear logic, while replacing LK
  5122 and Modal (thanks to Sara Kalvala);
  5123 
  5124 * HOL/Auth: correctness proofs for authentication protocols;
  5125 
  5126 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5127 examples on HOL/Auth);
  5128 
  5129 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5130 the rewriter and classical reasoner simultaneously;
  5131 
  5132 * function uresult no longer returns theorems in "standard" format;
  5133 regain previous version by: val uresult = standard o uresult;
  5134 
  5135 
  5136 
  5137 New in Isabelle94-6
  5138 -------------------
  5139 
  5140 * oracles -- these establish an interface between Isabelle and trusted
  5141 external reasoners, which may deliver results as theorems;
  5142 
  5143 * proof objects (in particular record all uses of oracles);
  5144 
  5145 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5146 
  5147 * "constdefs" section in theory files;
  5148 
  5149 * "primrec" section (HOL) no longer requires names;
  5150 
  5151 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5152 
  5153 
  5154 
  5155 New in Isabelle94-5
  5156 -------------------
  5157 
  5158 * reduced space requirements;
  5159 
  5160 * automatic HTML generation from theories;
  5161 
  5162 * theory files no longer require "..." (quotes) around most types;
  5163 
  5164 * new examples, including two proofs of the Church-Rosser theorem;
  5165 
  5166 * non-curried (1994) version of HOL is no longer distributed;
  5167 
  5168 
  5169 
  5170 New in Isabelle94-4
  5171 -------------------
  5172 
  5173 * greatly reduced space requirements;
  5174 
  5175 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5176 
  5177 * searchable theorem database (see the section "Retrieving theorems" on
  5178 page 8 of the Reference Manual);
  5179 
  5180 * new examples, including Grabczewski's monumental case study of the
  5181 Axiom of Choice;
  5182 
  5183 * The previous version of HOL renamed to Old_HOL;
  5184 
  5185 * The new version of HOL (previously called CHOL) uses a curried syntax
  5186 for functions.  Application looks like f a b instead of f(a,b);
  5187 
  5188 * Mutually recursive inductive definitions finally work in HOL;
  5189 
  5190 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5191 translates to the operator "split";
  5192 
  5193 
  5194 
  5195 New in Isabelle94-3
  5196 -------------------
  5197 
  5198 * new infix operator, addss, allowing the classical reasoner to
  5199 perform simplification at each step of its search.  Example:
  5200         fast_tac (cs addss ss)
  5201 
  5202 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5203 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5204 look like (a,b) instead of <a,b>;
  5205 
  5206 * PLEASE NOTE: CHOL will eventually replace HOL!
  5207 
  5208 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5209 It translates to the operator "split".  A new theory of integers is available;
  5210 
  5211 * In ZF, integer numerals now denote two's-complement binary integers.
  5212 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5213 
  5214 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5215 of the Axiom of Choice;
  5216 
  5217 
  5218 
  5219 New in Isabelle94-2
  5220 -------------------
  5221 
  5222 * Significantly faster resolution;
  5223 
  5224 * the different sections in a .thy file can now be mixed and repeated
  5225 freely;
  5226 
  5227 * Database of theorems for FOL, HOL and ZF.  New
  5228 commands including qed, qed_goal and bind_thm store theorems in the database.
  5229 
  5230 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5231 a given theory (thms_of), or find out what theory a theorem was proved in
  5232 (theory_of_thm);
  5233 
  5234 * Bugs fixed in the inductive definition and datatype packages;
  5235 
  5236 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5237 and HOL_dup_cs obsolete;
  5238 
  5239 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5240 have been removed;
  5241 
  5242 * Simpler definition of function space in ZF;
  5243 
  5244 * new results about cardinal and ordinal arithmetic in ZF;
  5245 
  5246 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5247 types;
  5248 
  5249 :mode=text:wrap=hard:maxLineLen=72:
  5250 
  5251 $Id$